ldso/ldso/ldso.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) 2005 by Joakim Tjernlund
   7  * Copyright (C) 2000-2004 by Erik Andersen <andersen@codepoet.org>
   8  * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
   9  *                              David Engel, Hongjiu Lu and Mitch D'Souza
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. The name of the above contributors may not be
  17  *    used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include "ldso.h"
  34 #include "unsecvars.h"
  35
  36 /* Pull in common debug code */
  37 #include "dl-debug.c"
  38
  39 #define ALLOW_ZERO_PLTGOT
  40
  41 /* Pull in the value of _dl_progname */
  42 #include LDSO_ELFINTERP
  43
  44 /* Global variables used within the shared library loader */
  45 char *_dl_library_path         = 0;     /* Where we look for libraries */
  46 char *_dl_preload              = 0;     /* Things to be loaded before the libs */
  47 char *_dl_ldsopath             = 0;     /* Location of the shared lib loader */
  48 int _dl_secure                 = 1;     /* Are we dealing with setuid stuff? */
  49 int _dl_errno                  = 0;     /* We can't use the real errno in ldso */
  50 size_t _dl_pagesize            = 0;     /* Store the page size for use later */
  51 struct r_debug *_dl_debug_addr = NULL;  /* Used to communicate with the gdb debugger */
  52 void *(*_dl_malloc_function) (size_t size) = NULL;
  53
  54 #ifdef __SUPPORT_LD_DEBUG__
  55 char *_dl_debug           = 0;
  56 char *_dl_debug_symbols   = 0;
  57 char *_dl_debug_move      = 0;
  58 char *_dl_debug_reloc     = 0;
  59 char *_dl_debug_detail    = 0;
  60 char *_dl_debug_nofixups  = 0;
  61 char *_dl_debug_bindings  = 0;
  62 int   _dl_debug_file      = 2;
  63 #endif
  64
  65 /* Needed for standalone execution. */
  66 unsigned long attribute_hidden _dl_skip_args = 0;
  67 const char *_dl_progname = UCLIBC_LDSO;      /* The name of the executable being run */
  68 #include "dl-startup.c"
  69 /* Forward function declarations */
  70 static int _dl_suid_ok(void);
  71
  72 /*
  73  * This stub function is used by some debuggers.  The idea is that they
  74  * can set an internal breakpoint on it, so that we are notified when the
  75  * address mapping is changed in some way.
  76  */
  77 void _dl_debug_state(void);
  78 void _dl_debug_state()
  79 {
  80 }
  81
  82 static unsigned char *_dl_malloc_addr = 0;      /* Lets _dl_malloc use the already allocated memory page */
  83 static unsigned char *_dl_mmap_zero   = 0;      /* Also used by _dl_malloc */
  84
  85 static struct elf_resolve **init_fini_list;
  86 static unsigned int nlist; /* # items in init_fini_list */
  87 extern void _start(void);
  88
  89 #ifdef __UCLIBC_HAS_SSP__
  90 #include <dl-osinfo.h>
  91 uintptr_t stack_chk_guard;
  92 # ifndef THREAD_SET_STACK_GUARD
  93 /* Only exported for architectures that don't store the stack guard canary
  94  * in local thread area.  */
  95 uintptr_t __stack_chk_guard attribute_relro;
  96 #  ifdef __UCLIBC_HAS_SSP_COMPAT__
  97 strong_alias(__stack_chk_guard,__guard)
  98 #  endif
  99 # elif __UCLIBC_HAS_SSP_COMPAT__
 100 uintptr_t __guard attribute_relro;
 101 # endif
 102 #endif
 103 #endif
 104
 105 static void _dl_run_array_forward(unsigned long array, unsigned long size,
 106                                   ElfW(Addr) loadaddr)
 107 {
 108         if (array != 0) {
 109                 unsigned int j;
 110                 unsigned int jm;
 111                 ElfW(Addr) *addrs;
 112                 jm = size / sizeof (ElfW(Addr));
 113                 addrs = (ElfW(Addr) *) (array + loadaddr);
 114                 for (j = 0; j < jm; ++j) {
 115                         void (*dl_elf_func) (void);
 116                         dl_elf_func = (void (*)(void)) (intptr_t) addrs[j];
 117                         (*dl_elf_func) ();
 118                 }
 119         }
 120 }
 121
 122 void _dl_run_init_array(struct elf_resolve *tpnt);
 123 void _dl_run_init_array(struct elf_resolve *tpnt)
 124 {
 125         _dl_run_array_forward(tpnt->dynamic_info[DT_INIT_ARRAY],
 126                               tpnt->dynamic_info[DT_INIT_ARRAYSZ],
 127                               tpnt->loadaddr);
 128 }
 129
 130 void _dl_app_init_array(void);
 131 void _dl_app_init_array(void)
 132 {
 133         _dl_run_init_array(_dl_loaded_modules);
 134 }
 135
 136 void _dl_run_fini_array(struct elf_resolve *tpnt);
 137 void _dl_run_fini_array(struct elf_resolve *tpnt)
 138 {
 139         if (tpnt->dynamic_info[DT_FINI_ARRAY]) {
 140                 ElfW(Addr) *array = (ElfW(Addr) *) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI_ARRAY]);
 141                 unsigned int i = (tpnt->dynamic_info[DT_FINI_ARRAYSZ] / sizeof(ElfW(Addr)));
 142                 while (i-- > 0) {
 143                         void (*dl_elf_func) (void);
 144                         dl_elf_func = (void (*)(void)) (intptr_t) array[i];
 145                         (*dl_elf_func) ();
 146                 }
 147         }
 148 }
 149
 150 void _dl_app_fini_array(void);
 151 void _dl_app_fini_array(void)
 152 {
 153         _dl_run_fini_array(_dl_loaded_modules);
 154 }
 155
 156 static void __attribute__ ((destructor)) __attribute_used__ _dl_fini(void)
 157 {
 158         int i;
 159         struct elf_resolve * tpnt;
 160
 161         for (i = 0; i < nlist; ++i) {
 162                 tpnt = init_fini_list[i];
 163                 if (tpnt->init_flag & FINI_FUNCS_CALLED)
 164                         continue;
 165                 tpnt->init_flag |= FINI_FUNCS_CALLED;
 166                 _dl_run_fini_array(tpnt);
 167                 if (tpnt->dynamic_info[DT_FINI]) {
 168                         void (*dl_elf_func) (void);
 169
 170                         dl_elf_func = (void (*)(void)) (intptr_t) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
 171                         _dl_if_debug_dprint("\ncalling FINI: %s\n\n", tpnt->libname);
 172                         (*dl_elf_func) ();
 173                 }
 174         }
 175 }
 176
 177 void _dl_get_ready_to_run(struct elf_resolve *tpnt, unsigned long load_addr,
 178                           ElfW(auxv_t) auxvt[AT_EGID + 1], char **envp,
 179                           char **argv)
 180 {
 181         ElfW(Phdr) *ppnt;
 182         ElfW(Dyn) *dpnt;
 183         char *lpntstr;
 184         unsigned int i;
 185         int unlazy = 0, trace_loaded_objects = 0;
 186         struct dyn_elf *rpnt;
 187         struct elf_resolve *tcurr;
 188         struct elf_resolve *tpnt1;
 189         struct elf_resolve app_tpnt_tmp;
 190         struct elf_resolve *app_tpnt = &app_tpnt_tmp;
 191         struct r_debug *debug_addr;
 192         unsigned long *lpnt;
 193         unsigned long *_dl_envp;                /* The environment address */
 194         ElfW(Addr) relro_addr = 0;
 195         size_t relro_size = 0;
 196
 197         /* Wahoo!!! We managed to make a function call!  Get malloc
 198          * setup so we can use _dl_dprintf() to print debug noise
 199          * instead of the SEND_STDERR macros used in dl-startup.c */
 200
 201         _dl_memset(app_tpnt, 0x00, sizeof(*app_tpnt));
 202
 203         /* Store the page size for later use */
 204         _dl_pagesize = (auxvt[AT_PAGESZ].a_un.a_val) ? (size_t) auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
 205         /* Make it so _dl_malloc can use the page of memory we have already
 206          * allocated.  We shouldn't need to grab any more memory.  This must
 207          * be first since things like _dl_dprintf() use _dl_malloc()...
 208          */
 209         _dl_malloc_addr = (unsigned char *)_dl_pagesize;
 210         _dl_mmap_zero = 0;
 211
 212         /* Wahoo!!! */
 213         _dl_debug_early("Cool, ldso survived making function calls\n");
 214
 215         /* Now we have done the mandatory linking of some things.  We are now
 216          * free to start using global variables, since these things have all
 217          * been fixed up by now.  Still no function calls outside of this
 218          * library, since the dynamic resolver is not yet ready.
 219          */
 220         if (argv[0]) {
 221                 _dl_progname = argv[0];
 222         }
 223
 224         if (_start == (void *) auxvt[AT_ENTRY].a_un.a_val) {
 225                 _dl_dprintf(_dl_debug_file, "Standalone execution is not supported yet\n");
 226                 _dl_exit(1);
 227         }
 228
 229         /* Start to build the tables of the modules that are required for
 230          * this beast to run.  We start with the basic executable, and then
 231          * go from there.  Eventually we will run across ourself, and we
 232          * will need to properly deal with that as well.
 233          */
 234         rpnt = NULL;
 235         if (_dl_getenv("LD_BIND_NOW", envp))
 236                 unlazy = RTLD_NOW;
 237
 238         /* Now we need to figure out what kind of options are selected.
 239          * Note that for SUID programs we ignore the settings in
 240          * LD_LIBRARY_PATH.
 241          */
 242         if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && _dl_suid_ok()) ||
 243             (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
 244              auxvt[AT_UID].a_un.a_val == auxvt[AT_EUID].a_un.a_val &&
 245              auxvt[AT_GID].a_un.a_val == auxvt[AT_EGID].a_un.a_val)) {
 246                 _dl_secure = 0;
 247                 _dl_preload = _dl_getenv("LD_PRELOAD", envp);
 248                 _dl_library_path = _dl_getenv("LD_LIBRARY_PATH", envp);
 249         } else {
 250                 static const char unsecure_envvars[] =
 251 #ifdef EXTRA_UNSECURE_ENVVARS
 252                         EXTRA_UNSECURE_ENVVARS
 253 #endif
 254                         UNSECURE_ENVVARS;
 255                 const char *nextp;
 256                 _dl_secure = 1;
 257
 258                 nextp = unsecure_envvars;
 259                 do {
 260                         _dl_unsetenv (nextp, envp);
 261                         /* We could use rawmemchr but this need not be fast.  */
 262                         nextp = (char *) _dl_strchr(nextp, '\0') + 1;
 263                 } while (*nextp != '\0');
 264                 _dl_preload = NULL;
 265                 _dl_library_path = NULL;
 266                 /* SUID binaries can be exploited if they do LAZY relocation. */
 267                 unlazy = RTLD_NOW;
 268         }
 269
 270         /* sjhill: your TLS init should go before this */
 271 #ifdef __UCLIBC_HAS_SSP__
 272         /* Set up the stack checker's canary.  */
 273         stack_chk_guard = _dl_setup_stack_chk_guard ();
 274 # ifdef THREAD_SET_STACK_GUARD
 275         THREAD_SET_STACK_GUARD (stack_chk_guard);
 276 #  ifdef __UCLIBC_HAS_SSP_COMPAT__
 277         __guard = stack_chk_guard;
 278 #  endif
 279 # else
 280         __stack_chk_guard = stack_chk_guard;
 281 # endif
 282 #endif
 283
 284         /* At this point we are now free to examine the user application,
 285          * and figure out which libraries are supposed to be called.  Until
 286          * we have this list, we will not be completely ready for dynamic
 287          * linking.
 288          */
 289
 290         /* Find the runtime load address of the main executable.  This may be
 291          * different from what the ELF header says for ET_DYN/PIE executables.
 292          */
 293         {
 294                 unsigned int idx;
 295                 ElfW(Phdr) *phdr = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 296
 297                 for (idx = 0; idx < auxvt[AT_PHNUM].a_un.a_val; idx++, phdr++)
 298                         if (phdr->p_type == PT_PHDR) {
 299                                 app_tpnt->loadaddr = (ElfW(Addr)) (auxvt[AT_PHDR].a_un.a_val - phdr->p_vaddr);
 300                                 break;
 301                         }
 302
 303                 if (app_tpnt->loadaddr)
 304                         _dl_debug_early("Position Independent Executable: "
 305                                         "app_tpnt->loadaddr=%x\n", app_tpnt->loadaddr);
 306         }
 307
 308         /*
 309          * This is used by gdb to locate the chain of shared libraries that are
 310          * currently loaded.
 311          */
 312         debug_addr = _dl_malloc(sizeof(struct r_debug));
 313         _dl_memset(debug_addr, 0, sizeof(struct r_debug));
 314
 315         ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 316         for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
 317                 if (ppnt->p_type == PT_GNU_RELRO) {
 318                         relro_addr = ppnt->p_vaddr;
 319                         relro_size = ppnt->p_memsz;
 320                 }
 321                 if (ppnt->p_type == PT_DYNAMIC) {
 322                         dpnt = (ElfW(Dyn) *) (ppnt->p_vaddr + app_tpnt->loadaddr);
 323                         _dl_parse_dynamic_info(dpnt, app_tpnt->dynamic_info, debug_addr, app_tpnt->loadaddr);
 324 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
 325                         /* Ugly, ugly.  We need to call mprotect to change the
 326                          * protection of the text pages so that we can do the
 327                          * dynamic linking.  We can set the protection back
 328                          * again once we are done.
 329                          */
 330                         _dl_debug_early("calling mprotect on the application program\n");
 331                         /* Now cover the application program. */
 332                         if (app_tpnt->dynamic_info[DT_TEXTREL]) {
 333                                 ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 334                                 for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
 335                                         if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
 336                                                 _dl_mprotect((void *) ((ppnt->p_vaddr + app_tpnt->loadaddr) & PAGE_ALIGN),
 337                                                              ((ppnt->p_vaddr + app_tpnt->loadaddr) & ADDR_ALIGN) +
 338                                                              (unsigned long) ppnt->p_filesz,
 339                                                              PROT_READ | PROT_WRITE | PROT_EXEC);
 340                                 }
 341                         }
 342 #endif
 343
 344 #ifndef ALLOW_ZERO_PLTGOT
 345                         /* make sure it's really there. */
 346                         if (app_tpnt->dynamic_info[DT_PLTGOT] == 0)
 347                                 continue;
 348 #endif
 349                         /* OK, we have what we need - slip this one into the list. */
 350                         app_tpnt = _dl_add_elf_hash_table(_dl_progname, (char *)app_tpnt->loadaddr,
 351                                         app_tpnt->dynamic_info, ppnt->p_vaddr + app_tpnt->loadaddr, ppnt->p_filesz);
 352                         _dl_loaded_modules->libtype = elf_executable;
 353                         _dl_loaded_modules->ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 354                         _dl_loaded_modules->n_phent = auxvt[AT_PHNUM].a_un.a_val;
 355                         _dl_symbol_tables = rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 356                         _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
 357                         rpnt->dyn = _dl_loaded_modules;
 358                         app_tpnt->rtld_flags = unlazy | RTLD_GLOBAL;
 359                         app_tpnt->usage_count++;
 360                         app_tpnt->symbol_scope = _dl_symbol_tables;
 361                         lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT]);
 362 #ifdef ALLOW_ZERO_PLTGOT
 363                         if (lpnt)
 364 #endif
 365                                 INIT_GOT(lpnt, _dl_loaded_modules);
 366                 }
 367
 368                 /* OK, fill this in - we did not have this before */
 369                 if (ppnt->p_type == PT_INTERP) {
 370                         char *ptmp;
 371
 372                         tpnt->libname = (char *) ppnt->p_vaddr + app_tpnt->loadaddr;
 373
 374                         /* Store the path where the shared lib loader was found
 375                          * for later use
 376                          */
 377                         _dl_ldsopath = _dl_strdup(tpnt->libname);
 378                         ptmp = _dl_strrchr(_dl_ldsopath, '/');
 379                         if (ptmp != _dl_ldsopath)
 380                                 *ptmp = '\0';
 381
 382                         _dl_debug_early("Lib Loader: (%x) %s\n", tpnt->loadaddr, tpnt->libname);
 383                 }
 384         }
 385         app_tpnt->relro_addr = relro_addr;
 386         app_tpnt->relro_size = relro_size;
 387
 388 #ifdef __SUPPORT_LD_DEBUG__
 389         _dl_debug = _dl_getenv("LD_DEBUG", envp);
 390         if (_dl_debug) {
 391                 if (_dl_strstr(_dl_debug, "all")) {
 392                         _dl_debug_detail = _dl_debug_move = _dl_debug_symbols
 393                                 = _dl_debug_reloc = _dl_debug_bindings = _dl_debug_nofixups = (void*)1;
 394                 } else {
 395                         _dl_debug_detail   = _dl_strstr(_dl_debug, "detail");
 396                         _dl_debug_move     = _dl_strstr(_dl_debug, "move");
 397                         _dl_debug_symbols  = _dl_strstr(_dl_debug, "sym");
 398                         _dl_debug_reloc    = _dl_strstr(_dl_debug, "reloc");
 399                         _dl_debug_nofixups = _dl_strstr(_dl_debug, "nofix");
 400                         _dl_debug_bindings = _dl_strstr(_dl_debug, "bind");
 401                 }
 402         }
 403
 404         {
 405                 const char *dl_debug_output;
 406
 407                 dl_debug_output = _dl_getenv("LD_DEBUG_OUTPUT", envp);
 408
 409                 if (dl_debug_output) {
 410                         char tmp[22], *tmp1, *filename;
 411                         int len1, len2;
 412
 413                         _dl_memset(tmp, 0, sizeof(tmp));
 414                         tmp1 = _dl_simple_ltoa( tmp, (unsigned long)_dl_getpid());
 415
 416                         len1 = _dl_strlen(dl_debug_output);
 417                         len2 = _dl_strlen(tmp1);
 418
 419                         filename = _dl_malloc(len1+len2+2);
 420
 421                         if (filename) {
 422                                 _dl_strcpy (filename, dl_debug_output);
 423                                 filename[len1] = '.';
 424                                 _dl_strcpy (&filename[len1+1], tmp1);
 425
 426                                 _dl_debug_file= _dl_open(filename, O_WRONLY|O_CREAT, 0644);
 427                                 if (_dl_debug_file < 0) {
 428                                         _dl_debug_file = 2;
 429                                         _dl_dprintf(_dl_debug_file, "can't open file: '%s'\n",filename);
 430                                 }
 431                         }
 432                 }
 433         }
 434 #endif
 435
 436         if (_dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL) {
 437                 trace_loaded_objects++;
 438         }
 439
 440 #ifndef __LDSO_LDD_SUPPORT__
 441         if (trace_loaded_objects) {
 442                 _dl_dprintf(_dl_debug_file, "Use the ldd provided by uClibc\n");
 443                 _dl_exit(1);
 444         }
 445 #endif
 446
 447         /*
 448          * OK, fix one more thing - set up debug_addr so it will point
 449          * to our chain.  Later we may need to fill in more fields, but this
 450          * should be enough for now.
 451          */
 452         debug_addr->r_map = (struct link_map *) _dl_loaded_modules;
 453         debug_addr->r_version = 1;
 454         debug_addr->r_ldbase = load_addr;
 455         debug_addr->r_brk = (unsigned long) &_dl_debug_state;
 456         _dl_debug_addr = debug_addr;
 457
 458         /* Notify the debugger we are in a consistant state */
 459         _dl_debug_addr->r_state = RT_CONSISTENT;
 460         _dl_debug_state();
 461
 462         /* OK, we now have the application in the list, and we have some
 463          * basic stuff in place.  Now search through the list for other shared
 464          * libraries that should be loaded, and insert them on the list in the
 465          * correct order.
 466          */
 467
 468         _dl_map_cache();
 469
 470         if (_dl_preload) {
 471                 char c, *str, *str2;
 472
 473                 str = _dl_preload;
 474                 while (*str == ':' || *str == ' ' || *str == '\t')
 475                         str++;
 476
 477                 while (*str) {
 478                         str2 = str;
 479                         while (*str2 && *str2 != ':' && *str2 != ' ' && *str2 != '\t')
 480                                 str2++;
 481                         c = *str2;
 482                         *str2 = '\0';
 483
 484                         if (!_dl_secure || _dl_strchr(str, '/') == NULL) {
 485                                 _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", str, _dl_progname);
 486
 487                                 tpnt1 = _dl_load_shared_library(_dl_secure, &rpnt, NULL, str, trace_loaded_objects);
 488                                 if (!tpnt1) {
 489 #ifdef __LDSO_LDD_SUPPORT__
 490                                         if (trace_loaded_objects)
 491                                                 _dl_dprintf(1, "\t%s => not found\n", str);
 492                                         else
 493 #endif
 494                                         {
 495                                                 _dl_dprintf(_dl_debug_file, "%s: can't load " "library '%s'\n", _dl_progname, str);
 496                                                 _dl_exit(15);
 497                                         }
 498                                 } else {
 499                                         tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 500
 501                                         _dl_debug_early("Loading: (%x) %s\n", tpnt1->loadaddr, tpnt1->libname);
 502
 503 #ifdef __LDSO_LDD_SUPPORT__
 504                                         if (trace_loaded_objects &&
 505                                             tpnt1->usage_count == 1) {
 506                                                 /* This is a real hack to make
 507                                                  * ldd not print the library
 508                                                  * itself when run on a
 509                                                  * library.
 510                                                  */
 511                                                 if (_dl_strcmp(_dl_progname, str) != 0)
 512                                                         _dl_dprintf(1, "\t%s => %s (%x)\n", str, tpnt1->libname,
 513                                                                     tpnt1->loadaddr);
 514                                         }
 515 #endif
 516                                 }
 517                         }
 518
 519                         *str2 = c;
 520                         str = str2;
 521                         while (*str == ':' || *str == ' ' || *str == '\t')
 522                                 str++;
 523                 }
 524         }
 525
 526 #ifdef __LDSO_PRELOAD_FILE_SUPPORT__
 527         do {
 528                 struct stat st;
 529                 char *preload;
 530                 int fd;
 531                 char c, *cp, *cp2;
 532
 533                 if (_dl_stat(LDSO_PRELOAD, &st) || st.st_size == 0) {
 534                         break;
 535                 }
 536
 537                 if ((fd = _dl_open(LDSO_PRELOAD, O_RDONLY, 0)) < 0) {
 538                         _dl_dprintf(_dl_debug_file, "%s: can't open file '%s'\n",
 539                                     _dl_progname, LDSO_PRELOAD);
 540                         break;
 541                 }
 542
 543                 preload = (caddr_t) _dl_mmap(0, st.st_size + 1,
 544                                              PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 545                 _dl_close(fd);
 546                 if (preload == (caddr_t) -1) {
 547                         _dl_dprintf(_dl_debug_file, "%s:%i: can't map '%s'\n",
 548                                     _dl_progname, __LINE__, LDSO_PRELOAD);
 549                         break;
 550                 }
 551
 552                 /* convert all separators and comments to spaces */
 553                 for (cp = preload; *cp; /*nada */ ) {
 554                         if (*cp == ':' || *cp == '\t' || *cp == '\n') {
 555                                 *cp++ = ' ';
 556                         } else if (*cp == '#') {
 557                                 do {
 558                                         *cp++ = ' ';
 559                                 } while (*cp != '\n' && *cp != '\0');
 560                         } else {
 561                                 cp++;
 562                         }
 563                 }
 564
 565                 /* find start of first library */
 566                 for (cp = preload; *cp && *cp == ' '; cp++)
 567                         /*nada */ ;
 568
 569                 while (*cp) {
 570                         /* find end of library */
 571                         for (cp2 = cp; *cp && *cp != ' '; cp++)
 572                                 /*nada */ ;
 573                         c = *cp;
 574                         *cp = '\0';
 575
 576                         _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", cp2, _dl_progname);
 577
 578                         tpnt1 = _dl_load_shared_library(0, &rpnt, NULL, cp2, trace_loaded_objects);
 579                         if (!tpnt1) {
 580 #ifdef __LDSO_LDD_SUPPORT__
 581                                 if (trace_loaded_objects)
 582                                         _dl_dprintf(1, "\t%s => not found\n", cp2);
 583                                 else
 584 #endif
 585                                 {
 586                                         _dl_dprintf(_dl_debug_file, "%s: can't load library '%s'\n", _dl_progname, cp2);
 587                                         _dl_exit(15);
 588                                 }
 589                         } else {
 590                                 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 591
 592                                 _dl_debug_early("Loading: (%x) %s\n", tpnt1->loadaddr, tpnt1->libname);
 593
 594 #ifdef __LDSO_LDD_SUPPORT__
 595                                 if (trace_loaded_objects &&
 596                                     tpnt1->usage_count == 1) {
 597                                         _dl_dprintf(1, "\t%s => %s (%x)\n",
 598                                                     cp2, tpnt1->libname,
 599                                                     (unsigned)tpnt1->loadaddr);
 600                                 }
 601 #endif
 602                         }
 603
 604                         /* find start of next library */
 605                         *cp = c;
 606                         for ( /*nada */ ; *cp && *cp == ' '; cp++)
 607                                 /*nada */ ;
 608                 }
 609
 610                 _dl_munmap(preload, st.st_size + 1);
 611         } while (0);
 612 #endif /* __LDSO_PRELOAD_FILE_SUPPORT__ */
 613
 614         nlist = 0;
 615         for (tcurr = _dl_loaded_modules; tcurr; tcurr = tcurr->next) {
 616                 ElfW(Dyn) *this_dpnt;
 617
 618                 nlist++;
 619                 for (this_dpnt = (ElfW(Dyn) *) tcurr->dynamic_addr; this_dpnt->d_tag; this_dpnt++) {
 620                         if (this_dpnt->d_tag == DT_NEEDED) {
 621                                 char *name;
 622                                 struct init_fini_list *tmp;
 623
 624                                 lpntstr = (char*) (tcurr->dynamic_info[DT_STRTAB] + this_dpnt->d_un.d_val);
 625                                 name = _dl_get_last_path_component(lpntstr);
 626                                 if (_dl_strcmp(name, UCLIBC_LDSO) == 0)
 627                                         continue;
 628
 629                                 _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", lpntstr, _dl_progname);
 630
 631                                 if (!(tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, trace_loaded_objects))) {
 632 #ifdef __LDSO_LDD_SUPPORT__
 633                                         if (trace_loaded_objects) {
 634                                                 _dl_dprintf(1, "\t%s => not found\n", lpntstr);
 635                                                 continue;
 636                                         } else
 637 #endif
 638                                         {
 639                                                 _dl_dprintf(_dl_debug_file, "%s: can't load library '%s'\n", _dl_progname, lpntstr);
 640                                                 _dl_exit(16);
 641                                         }
 642                                 }
 643
 644                                 tmp = alloca(sizeof(struct init_fini_list)); /* Allocates on stack, no need to free this memory */
 645                                 tmp->tpnt = tpnt1;
 646                                 tmp->next = tcurr->init_fini;
 647                                 tcurr->init_fini = tmp;
 648
 649                                 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 650
 651                                 _dl_debug_early("Loading: (%x) %s\n", tpnt1->loadaddr, tpnt1->libname);
 652
 653 #ifdef __LDSO_LDD_SUPPORT__
 654                                 if (trace_loaded_objects &&
 655                                     tpnt1->usage_count == 1) {
 656                                         _dl_dprintf(1, "\t%s => %s (%x)\n",
 657                                                     lpntstr, tpnt1->libname,
 658                                                     (unsigned)tpnt1->loadaddr);
 659                                 }
 660 #endif
 661                         }
 662                 }
 663         }
 664         _dl_unmap_cache();
 665
 666         --nlist; /* Exclude the application. */
 667         init_fini_list = _dl_malloc(nlist * sizeof(struct elf_resolve *));
 668         i = 0;
 669         for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
 670                 init_fini_list[i++] = tcurr;
 671         }
 672
 673         /* Sort the INIT/FINI list in dependency order. */
 674         for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
 675                 int j, k;
 676
 677                 for (j = 0; init_fini_list[j] != tcurr; ++j)
 678                         /* Empty */;
 679                 for (k = j + 1; k < nlist; ++k) {
 680                         struct init_fini_list *runp = init_fini_list[k]->init_fini;
 681
 682                         for (; runp; runp = runp->next) {
 683                                 if (runp->tpnt == tcurr) {
 684                                         struct elf_resolve *here = init_fini_list[k];
 685                                         _dl_if_debug_dprint("Move %s from pos %d to %d in INIT/FINI list\n", here->libname, k, j);
 686                                         for (i = (k - j); i; --i)
 687                                                 init_fini_list[i+j] = init_fini_list[i+j-1];
 688                                         init_fini_list[j] = here;
 689                                         ++j;
 690                                         break;
 691                                 }
 692                         }
 693                 }
 694         }
 695 #ifdef __SUPPORT_LD_DEBUG__
 696         if(_dl_debug) {
 697                 _dl_dprintf(_dl_debug_file, "\nINIT/FINI order and dependencies:\n");
 698                 for (i = 0; i < nlist; i++) {
 699                         struct init_fini_list *tmp;
 700
 701                         _dl_dprintf(_dl_debug_file, "lib: %s has deps:\n",
 702                                     init_fini_list[i]->libname);
 703                         tmp = init_fini_list[i]->init_fini;
 704                         for (; tmp; tmp = tmp->next)
 705                                 _dl_dprintf(_dl_debug_file, " %s ", tmp->tpnt->libname);
 706                         _dl_dprintf(_dl_debug_file, "\n");
 707                 }
 708         }
 709 #endif
 710
 711         /*
 712          * If the program interpreter is not in the module chain, add it.
 713          * This will be required for dlopen to be able to access the internal
 714          * functions in the dynamic linker and to relocate the interpreter
 715          * again once all libs are loaded.
 716          */
 717         if (tpnt) {
 718                 ElfW(Ehdr) *epnt = (ElfW(Ehdr) *) auxvt[AT_BASE].a_un.a_val;
 719                 ElfW(Phdr) *myppnt = (ElfW(Phdr) *) (load_addr + epnt->e_phoff);
 720                 int j;
 721
 722                 tpnt = _dl_add_elf_hash_table(tpnt->libname, (char *)load_addr,
 723                                               tpnt->dynamic_info,
 724                                               (unsigned long)tpnt->dynamic_addr,
 725                                               0);
 726
 727                 tpnt->n_phent = epnt->e_phnum;
 728                 tpnt->ppnt = myppnt;
 729                 for (j = 0; j < epnt->e_phnum; j++, myppnt++) {
 730                         if (myppnt->p_type ==  PT_GNU_RELRO) {
 731                                 tpnt->relro_addr = myppnt->p_vaddr;
 732                                 tpnt->relro_size = myppnt->p_memsz;
 733                                 break;
 734                         }
 735                 }
 736                 tpnt->libtype = program_interpreter;
 737                 tpnt->usage_count++;
 738                 tpnt->symbol_scope = _dl_symbol_tables;
 739                 if (rpnt) {
 740                         rpnt->next = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 741                         _dl_memset(rpnt->next, 0, sizeof(struct dyn_elf));
 742                         rpnt->next->prev = rpnt;
 743                         rpnt = rpnt->next;
 744                 } else {
 745                         rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 746                         _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
 747                 }
 748                 rpnt->dyn = tpnt;
 749                 tpnt->rtld_flags = RTLD_NOW | RTLD_GLOBAL; /* Must not be LAZY */
 750 #ifdef RERELOCATE_LDSO
 751                 /* Only rerelocate functions for now. */
 752                 tpnt->init_flag = RELOCS_DONE;
 753                 lpnt = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT]);
 754 # ifdef ALLOW_ZERO_PLTGOT
 755                 if (tpnt->dynamic_info[DT_PLTGOT])
 756 # endif
 757                         INIT_GOT(lpnt, tpnt);
 758 #else
 759                 tpnt->init_flag = RELOCS_DONE | JMP_RELOCS_DONE;
 760 #endif
 761                 tpnt = NULL;
 762         }
 763
 764 #ifdef __LDSO_LDD_SUPPORT__
 765         /* End of the line for ldd.... */
 766         if (trace_loaded_objects) {
 767                 _dl_dprintf(1, "\t%s => %s (%x)\n",
 768                             rpnt->dyn->libname + _dl_strlen(_dl_ldsopath) + 1,
 769                             rpnt->dyn->libname, rpnt->dyn->loadaddr);
 770                 _dl_exit(0);
 771         }
 772 #endif
 773
 774         _dl_debug_early("Beginning relocation fixups\n");
 775
 776 #ifdef __mips__
 777         /*
 778          * Relocation of the GOT entries for MIPS have to be done
 779          * after all the libraries have been loaded.
 780          */
 781         _dl_perform_mips_global_got_relocations(_dl_loaded_modules, !unlazy);
 782 #endif
 783
 784         /*
 785          * OK, now all of the kids are tucked into bed in their proper
 786          * addresses.  Now we go through and look for REL and RELA records that
 787          * indicate fixups to the GOT tables.  We need to do this in reverse
 788          * order so that COPY directives work correctly.
 789          */
 790         if (_dl_symbol_tables)
 791                 if (_dl_fixup(_dl_symbol_tables, unlazy))
 792                         _dl_exit(-1);
 793
 794         for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 795                 if (tpnt->relro_size)
 796                         _dl_protect_relro (tpnt);
 797         }
 798
 799         /* OK, at this point things are pretty much ready to run.  Now we need
 800          * to touch up a few items that are required, and then we can let the
 801          * user application have at it.  Note that the dynamic linker itself
 802          * is not guaranteed to be fully dynamicly linked if we are using
 803          * ld.so.1, so we have to look up each symbol individually.
 804          */
 805
 806         _dl_envp = (unsigned long *) (intptr_t) _dl_find_hash("__environ", _dl_symbol_tables, NULL, 0);
 807         if (_dl_envp)
 808                 *_dl_envp = (unsigned long) envp;
 809
 810 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
 811         {
 812                 unsigned int j;
 813                 ElfW(Phdr) *myppnt;
 814
 815                 /* We had to set the protections of all pages to R/W for
 816                  * dynamic linking.  Set text pages back to R/O.
 817                  */
 818                 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 819                         for (myppnt = tpnt->ppnt, j = 0; j < tpnt->n_phent; j++, myppnt++) {
 820                                 if (myppnt->p_type == PT_LOAD && !(myppnt->p_flags & PF_W) && tpnt->dynamic_info[DT_TEXTREL]) {
 821                                         _dl_mprotect((void *) (tpnt->loadaddr + (myppnt->p_vaddr & PAGE_ALIGN)),
 822                                                         (myppnt->p_vaddr & ADDR_ALIGN) + (unsigned long) myppnt->p_filesz, LXFLAGS(myppnt->p_flags));
 823                                 }
 824                         }
 825                 }
 826
 827         }
 828 #endif
 829         /* Notify the debugger we have added some objects. */
 830         _dl_debug_addr->r_state = RT_ADD;
 831         _dl_debug_state();
 832
 833         /* Run pre-initialization functions for the executable.  */
 834         _dl_run_array_forward(_dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAY],
 835                               _dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAYSZ],
 836                               _dl_loaded_modules->loadaddr);
 837
 838         /* Run initialization functions for loaded objects.  For the
 839            main executable, they will be run from __uClibc_main.  */
 840         for (i = nlist; i; --i) {
 841                 tpnt = init_fini_list[i-1];
 842                 tpnt->init_fini = NULL; /* Clear, since alloca was used */
 843                 if (tpnt->init_flag & INIT_FUNCS_CALLED)
 844                         continue;
 845                 tpnt->init_flag |= INIT_FUNCS_CALLED;
 846
 847                 if (tpnt->dynamic_info[DT_INIT]) {
 848                         void (*dl_elf_func) (void);
 849
 850                         dl_elf_func = (void (*)(void)) (intptr_t) (tpnt->loadaddr + tpnt->dynamic_info[DT_INIT]);
 851
 852                         _dl_if_debug_dprint("calling INIT: %s\n\n", tpnt->libname);
 853
 854                         (*dl_elf_func) ();
 855                 }
 856
 857                 _dl_run_init_array(tpnt);
 858         }
 859
 860         /* Find the real malloc function and make ldso functions use that from now on */
 861          _dl_malloc_function = (void* (*)(size_t)) (intptr_t) _dl_find_hash("malloc",
 862                          _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT);
 863
 864         /* Notify the debugger that all objects are now mapped in.  */
 865         _dl_debug_addr->r_state = RT_CONSISTENT;
 866         _dl_debug_state();
 867 }
 868
 869 char *_dl_getenv(const char *symbol, char **envp)
 870 {
 871         char *pnt;
 872         const char *pnt1;
 873
 874         while ((pnt = *envp++)) {
 875                 pnt1 = symbol;
 876                 while (*pnt && *pnt == *pnt1)
 877                         pnt1++, pnt++;
 878                 if (!*pnt || *pnt != '=' || *pnt1)
 879                         continue;
 880                 return pnt + 1;
 881         }
 882         return 0;
 883 }
 884
 885 void _dl_unsetenv(const char *symbol, char **envp)
 886 {
 887         char *pnt;
 888         const char *pnt1;
 889         char **newenvp = envp;
 890
 891         for (pnt = *envp; pnt; pnt = *++envp) {
 892                 pnt1 = symbol;
 893                 while (*pnt && *pnt == *pnt1)
 894                         pnt1++, pnt++;
 895                 if (!*pnt || *pnt != '=' || *pnt1)
 896                         *newenvp++ = *envp;
 897         }
 898         *newenvp++ = *envp;
 899         return;
 900 }
 901
 902 static int _dl_suid_ok(void)
 903 {
 904         __kernel_uid_t uid, euid;
 905         __kernel_gid_t gid, egid;
 906
 907         uid = _dl_getuid();
 908         euid = _dl_geteuid();
 909         gid = _dl_getgid();
 910         egid = _dl_getegid();
 911
 912         if(uid == euid && gid == egid) {
 913                 return 1;
 914         }
 915         return 0;
 916 }
 917
 918 void *_dl_malloc(int size)
 919 {
 920         void *retval;
 921
 922 #if 0
 923         _dl_debug_early("request for %d bytes\n", size);
 924 #endif
 925
 926         if (_dl_malloc_function)
 927                 return (*_dl_malloc_function) (size);
 928
 929         if (_dl_malloc_addr - _dl_mmap_zero + (unsigned)size > _dl_pagesize) {
 930                 _dl_debug_early("mmapping more memory\n");
 931                 _dl_mmap_zero = _dl_malloc_addr = _dl_mmap((void *) 0, size,
 932                                 PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 933                 if (_dl_mmap_check_error(_dl_mmap_zero)) {
 934                         _dl_dprintf(_dl_debug_file, "%s: mmap of a spare page failed!\n", _dl_progname);
 935                         _dl_exit(20);
 936                 }
 937         }
 938         retval = _dl_malloc_addr;
 939         _dl_malloc_addr += size;
 940
 941         /*
 942          * Align memory to 4 byte boundary.  Some platforms require this,
 943          * others simply get better performance.
 944          */
 945         _dl_malloc_addr = (unsigned char *) (((unsigned long) _dl_malloc_addr + 3) & ~(3));
 946         return retval;
 947 }
 948
 949 #include "dl-hash.c"
 950 #include "dl-elf.c"