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) 2000-2006 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 void (*_dl_free_function) (void *p) = NULL;
  54
  55 #ifdef __SUPPORT_LD_DEBUG__
  56 char *_dl_debug           = 0;
  57 char *_dl_debug_symbols   = 0;
  58 char *_dl_debug_move      = 0;
  59 char *_dl_debug_reloc     = 0;
  60 char *_dl_debug_detail    = 0;
  61 char *_dl_debug_nofixups  = 0;
  62 char *_dl_debug_bindings  = 0;
  63 int   _dl_debug_file      = 2;
  64 #endif
  65
  66 /* Needed for standalone execution. */
  67 unsigned long attribute_hidden _dl_skip_args = 0;
  68 const char *_dl_progname = UCLIBC_LDSO;      /* The name of the executable being run */
  69 #include "dl-startup.c"
  70 #include "dl-array.c"
  71 /* Forward function declarations */
  72 static int _dl_suid_ok(void);
  73
  74 /*
  75  * This stub function is used by some debuggers.  The idea is that they
  76  * can set an internal breakpoint on it, so that we are notified when the
  77  * address mapping is changed in some way.
  78  */
  79 void _dl_debug_state(void);
  80 rtld_hidden_proto(_dl_debug_state, noinline);
  81 void _dl_debug_state(void)
  82 {
  83         /* Make sure GCC doesn't recognize this function as pure, to avoid
  84          * having the calls optimized away.
  85          */
  86         __asm__("");
  87 }
  88 rtld_hidden_def(_dl_debug_state);
  89
  90 static unsigned char *_dl_malloc_addr = 0;      /* Lets _dl_malloc use the already allocated memory page */
  91 static unsigned char *_dl_mmap_zero   = 0;      /* Also used by _dl_malloc */
  92
  93 static struct elf_resolve **init_fini_list;
  94 static unsigned int nlist; /* # items in init_fini_list */
  95 extern void _start(void);
  96
  97 #ifdef __UCLIBC_HAS_SSP__
  98 # include <dl-osinfo.h>
  99 uintptr_t stack_chk_guard;
 100 # ifndef THREAD_SET_STACK_GUARD
 101 /* Only exported for architectures that don't store the stack guard canary
 102  * in local thread area.  */
 103 uintptr_t __stack_chk_guard attribute_relro;
 104 #  ifdef __UCLIBC_HAS_SSP_COMPAT__
 105 strong_alias(__stack_chk_guard,__guard)
 106 #  endif
 107 # elif __UCLIBC_HAS_SSP_COMPAT__
 108 uintptr_t __guard attribute_relro;
 109 # endif
 110 #endif
 111
 112 static void __attribute__ ((destructor)) __attribute_used__ _dl_fini(void)
 113 {
 114         int i;
 115         struct elf_resolve * tpnt;
 116
 117         for (i = 0; i < nlist; ++i) {
 118                 tpnt = init_fini_list[i];
 119                 if (tpnt->init_flag & FINI_FUNCS_CALLED)
 120                         continue;
 121                 tpnt->init_flag |= FINI_FUNCS_CALLED;
 122                 _dl_run_fini_array(tpnt);
 123                 if (tpnt->dynamic_info[DT_FINI]) {
 124                         void (*dl_elf_func) (void);
 125
 126                         dl_elf_func = (void (*)(void)) (intptr_t) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_FINI]);
 127                         _dl_if_debug_dprint("\ncalling FINI: %s\n\n", tpnt->libname);
 128                         DL_CALL_FUNC_AT_ADDR (dl_elf_func, tpnt->loadaddr, (void(*)(void)));
 129                 }
 130         }
 131 }
 132
 133 void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr,
 134                           ElfW(auxv_t) auxvt[AT_EGID + 1], char **envp,
 135                           char **argv)
 136 {
 137         ElfW(Phdr) *ppnt;
 138         ElfW(Dyn) *dpnt;
 139         char *lpntstr;
 140         unsigned int i;
 141         int unlazy = 0, trace_loaded_objects = 0;
 142         struct dyn_elf *rpnt;
 143         struct elf_resolve *tcurr;
 144         struct elf_resolve *tpnt1;
 145         struct elf_resolve app_tpnt_tmp;
 146         struct elf_resolve *app_tpnt = &app_tpnt_tmp;
 147         struct r_debug *debug_addr;
 148         unsigned long *lpnt;
 149         unsigned long *_dl_envp;                /* The environment address */
 150         ElfW(Addr) relro_addr = 0;
 151         size_t relro_size = 0;
 152         struct stat st;
 153
 154         /* Wahoo!!! We managed to make a function call!  Get malloc
 155          * setup so we can use _dl_dprintf() to print debug noise
 156          * instead of the SEND_STDERR macros used in dl-startup.c */
 157
 158         _dl_memset(app_tpnt, 0x00, sizeof(*app_tpnt));
 159
 160         /* Store the page size for later use */
 161         _dl_pagesize = (auxvt[AT_PAGESZ].a_un.a_val) ? (size_t) auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
 162         /* Make it so _dl_malloc can use the page of memory we have already
 163          * allocated.  We shouldn't need to grab any more memory.  This must
 164          * be first since things like _dl_dprintf() use _dl_malloc()...
 165          */
 166         _dl_malloc_addr = (unsigned char *)_dl_pagesize;
 167         _dl_mmap_zero = 0;
 168
 169         /* Wahoo!!! */
 170         _dl_debug_early("Cool, ldso survived making function calls\n");
 171
 172         /* Now we have done the mandatory linking of some things.  We are now
 173          * free to start using global variables, since these things have all
 174          * been fixed up by now.  Still no function calls outside of this
 175          * library, since the dynamic resolver is not yet ready.
 176          */
 177         if (argv[0]) {
 178                 _dl_progname = argv[0];
 179         }
 180
 181         if (_start == (void *) auxvt[AT_ENTRY].a_un.a_val) {
 182                 _dl_dprintf(_dl_debug_file, "Standalone execution is not supported yet\n");
 183                 _dl_exit(1);
 184         }
 185
 186         /* Start to build the tables of the modules that are required for
 187          * this beast to run.  We start with the basic executable, and then
 188          * go from there.  Eventually we will run across ourself, and we
 189          * will need to properly deal with that as well.
 190          */
 191         rpnt = NULL;
 192         if (_dl_getenv("LD_BIND_NOW", envp))
 193                 unlazy = RTLD_NOW;
 194
 195         /* Now we need to figure out what kind of options are selected.
 196          * Note that for SUID programs we ignore the settings in
 197          * LD_LIBRARY_PATH.
 198          */
 199         if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && _dl_suid_ok()) ||
 200             (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
 201              auxvt[AT_UID].a_un.a_val == auxvt[AT_EUID].a_un.a_val &&
 202              auxvt[AT_GID].a_un.a_val == auxvt[AT_EGID].a_un.a_val)) {
 203                 _dl_secure = 0;
 204                 _dl_preload = _dl_getenv("LD_PRELOAD", envp);
 205                 _dl_library_path = _dl_getenv("LD_LIBRARY_PATH", envp);
 206         } else {
 207                 static const char unsecure_envvars[] =
 208 #ifdef EXTRA_UNSECURE_ENVVARS
 209                         EXTRA_UNSECURE_ENVVARS
 210 #endif
 211                         UNSECURE_ENVVARS;
 212                 const char *nextp;
 213                 _dl_secure = 1;
 214
 215                 nextp = unsecure_envvars;
 216                 do {
 217                         _dl_unsetenv (nextp, envp);
 218                         /* We could use rawmemchr but this need not be fast.  */
 219                         nextp = (char *) _dl_strchr(nextp, '\0') + 1;
 220                 } while (*nextp != '\0');
 221                 _dl_preload = NULL;
 222                 _dl_library_path = NULL;
 223                 /* SUID binaries can be exploited if they do LAZY relocation. */
 224                 unlazy = RTLD_NOW;
 225         }
 226
 227         /* sjhill: your TLS init should go before this */
 228 #ifdef __UCLIBC_HAS_SSP__
 229         /* Set up the stack checker's canary.  */
 230         stack_chk_guard = _dl_setup_stack_chk_guard ();
 231 # ifdef THREAD_SET_STACK_GUARD
 232         THREAD_SET_STACK_GUARD (stack_chk_guard);
 233 #  ifdef __UCLIBC_HAS_SSP_COMPAT__
 234         __guard = stack_chk_guard;
 235 #  endif
 236 # else
 237         __stack_chk_guard = stack_chk_guard;
 238 # endif
 239 #endif
 240
 241         /* At this point we are now free to examine the user application,
 242          * and figure out which libraries are supposed to be called.  Until
 243          * we have this list, we will not be completely ready for dynamic
 244          * linking.
 245          */
 246
 247         /* Find the runtime load address of the main executable.  This may be
 248          * different from what the ELF header says for ET_DYN/PIE executables.
 249          */
 250         {
 251                 unsigned int idx;
 252                 ElfW(Phdr) *phdr = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 253
 254                 for (idx = 0; idx < auxvt[AT_PHNUM].a_un.a_val; idx++, phdr++)
 255                         if (phdr->p_type == PT_PHDR) {
 256                                 DL_INIT_LOADADDR_PROG(app_tpnt->loadaddr, auxvt[AT_PHDR].a_un.a_val - phdr->p_vaddr);
 257                                 break;
 258                         }
 259
 260                 if (DL_LOADADDR_BASE(app_tpnt->loadaddr))
 261                         _dl_debug_early("Position Independent Executable: "
 262                                         "app_tpnt->loadaddr=%x\n", DL_LOADADDR_BASE(app_tpnt->loadaddr));
 263         }
 264
 265         /*
 266          * This is used by gdb to locate the chain of shared libraries that are
 267          * currently loaded.
 268          */
 269         debug_addr = _dl_malloc(sizeof(struct r_debug));
 270         _dl_memset(debug_addr, 0, sizeof(struct r_debug));
 271
 272         ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 273         for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
 274                 if (ppnt->p_type == PT_GNU_RELRO) {
 275                         relro_addr = ppnt->p_vaddr;
 276                         relro_size = ppnt->p_memsz;
 277                 }
 278                 if (ppnt->p_type == PT_DYNAMIC) {
 279                         dpnt = (ElfW(Dyn) *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
 280                         _dl_parse_dynamic_info(dpnt, app_tpnt->dynamic_info, debug_addr, app_tpnt->loadaddr);
 281 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
 282                         /* Ugly, ugly.  We need to call mprotect to change the
 283                          * protection of the text pages so that we can do the
 284                          * dynamic linking.  We can set the protection back
 285                          * again once we are done.
 286                          */
 287                         _dl_debug_early("calling mprotect on the application program\n");
 288                         /* Now cover the application program. */
 289                         if (app_tpnt->dynamic_info[DT_TEXTREL]) {
 290                                 ElfW(Phdr) *ppnt_outer = ppnt;
 291                                 ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 292                                 for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
 293                                         if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
 294                                                 _dl_mprotect((void *) (DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr) & PAGE_ALIGN),
 295                                                              ((ppnt->p_vaddr + app_tpnt->loadaddr) & ADDR_ALIGN) +
 296                                                              (unsigned long) ppnt->p_filesz,
 297                                                              PROT_READ | PROT_WRITE | PROT_EXEC);
 298                                 }
 299                                 ppnt = ppnt_outer;
 300                         }
 301 #else
 302                         if (app_tpnt->dynamic_info[DT_TEXTREL]) {
 303                                 _dl_dprintf(_dl_debug_file, "Can't modify application's text section; use the GCC option -fPIE for position-independent executables.\n");
 304                                 _dl_exit(1);
 305                         }
 306 #endif
 307
 308 #ifndef ALLOW_ZERO_PLTGOT
 309                         /* make sure it's really there. */
 310                         if (app_tpnt->dynamic_info[DT_PLTGOT] == 0)
 311                                 continue;
 312 #endif
 313                         /* OK, we have what we need - slip this one into the list. */
 314                         app_tpnt = _dl_add_elf_hash_table(_dl_progname, app_tpnt->loadaddr,
 315                                         app_tpnt->dynamic_info,
 316                                         DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr),
 317                                         ppnt->p_filesz);
 318                         _dl_loaded_modules->libtype = elf_executable;
 319                         _dl_loaded_modules->ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 320                         _dl_loaded_modules->n_phent = auxvt[AT_PHNUM].a_un.a_val;
 321                         _dl_symbol_tables = rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 322                         _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
 323                         rpnt->dyn = _dl_loaded_modules;
 324                         app_tpnt->rtld_flags = unlazy | RTLD_GLOBAL;
 325                         app_tpnt->usage_count++;
 326                         app_tpnt->symbol_scope = _dl_symbol_tables;
 327                         lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT]);
 328 #ifdef ALLOW_ZERO_PLTGOT
 329                         if (lpnt)
 330 #endif
 331                                 INIT_GOT(lpnt, _dl_loaded_modules);
 332                 }
 333
 334                 /* OK, fill this in - we did not have this before */
 335                 if (ppnt->p_type == PT_INTERP) {
 336                         char *ptmp;
 337
 338                         tpnt->libname = (char *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
 339
 340                         /* Store the path where the shared lib loader was found
 341                          * for later use
 342                          */
 343                         _dl_ldsopath = _dl_strdup(tpnt->libname);
 344                         ptmp = _dl_strrchr(_dl_ldsopath, '/');
 345                         if (ptmp != _dl_ldsopath)
 346                                 *ptmp = '\0';
 347
 348                         _dl_debug_early("Lib Loader: (%x) %s\n", DL_LOADADDR_BASE(tpnt->loadaddr), tpnt->libname);
 349                 }
 350         }
 351         app_tpnt->relro_addr = relro_addr;
 352         app_tpnt->relro_size = relro_size;
 353
 354 #ifdef __SUPPORT_LD_DEBUG__
 355         _dl_debug = _dl_getenv("LD_DEBUG", envp);
 356         if (_dl_debug) {
 357                 if (_dl_strstr(_dl_debug, "all")) {
 358                         _dl_debug_detail = _dl_debug_move = _dl_debug_symbols
 359                                 = _dl_debug_reloc = _dl_debug_bindings = _dl_debug_nofixups = (void*)1;
 360                 } else {
 361                         _dl_debug_detail   = _dl_strstr(_dl_debug, "detail");
 362                         _dl_debug_move     = _dl_strstr(_dl_debug, "move");
 363                         _dl_debug_symbols  = _dl_strstr(_dl_debug, "sym");
 364                         _dl_debug_reloc    = _dl_strstr(_dl_debug, "reloc");
 365                         _dl_debug_nofixups = _dl_strstr(_dl_debug, "nofix");
 366                         _dl_debug_bindings = _dl_strstr(_dl_debug, "bind");
 367                 }
 368         }
 369
 370         {
 371                 const char *dl_debug_output;
 372
 373                 dl_debug_output = _dl_getenv("LD_DEBUG_OUTPUT", envp);
 374
 375                 if (dl_debug_output) {
 376                         char tmp[22], *tmp1, *filename;
 377                         int len1, len2;
 378
 379                         _dl_memset(tmp, 0, sizeof(tmp));
 380                         tmp1 = _dl_simple_ltoa( tmp, (unsigned long)_dl_getpid());
 381
 382                         len1 = _dl_strlen(dl_debug_output);
 383                         len2 = _dl_strlen(tmp1);
 384
 385                         filename = _dl_malloc(len1+len2+2);
 386
 387                         if (filename) {
 388                                 _dl_strcpy (filename, dl_debug_output);
 389                                 filename[len1] = '.';
 390                                 _dl_strcpy (&filename[len1+1], tmp1);
 391
 392                                 _dl_debug_file= _dl_open(filename, O_WRONLY|O_CREAT, 0644);
 393                                 if (_dl_debug_file < 0) {
 394                                         _dl_debug_file = 2;
 395                                         _dl_dprintf(_dl_debug_file, "can't open file: '%s'\n",filename);
 396                                 }
 397                         }
 398                 }
 399         }
 400 #endif
 401
 402         if (_dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL) {
 403                 trace_loaded_objects++;
 404         }
 405
 406 #ifndef __LDSO_LDD_SUPPORT__
 407         if (trace_loaded_objects) {
 408                 _dl_dprintf(_dl_debug_file, "Use the ldd provided by uClibc\n");
 409                 _dl_exit(1);
 410         }
 411 #endif
 412
 413         /*
 414          * OK, fix one more thing - set up debug_addr so it will point
 415          * to our chain.  Later we may need to fill in more fields, but this
 416          * should be enough for now.
 417          */
 418         debug_addr->r_map = (struct link_map *) _dl_loaded_modules;
 419         debug_addr->r_version = 1;
 420         debug_addr->r_ldbase = DL_LOADADDR_BASE(load_addr);
 421         debug_addr->r_brk = (unsigned long) &_dl_debug_state;
 422         _dl_debug_addr = debug_addr;
 423
 424         /* Notify the debugger we are in a consistant state */
 425         _dl_debug_addr->r_state = RT_CONSISTENT;
 426         _dl_debug_state();
 427
 428         /* OK, we now have the application in the list, and we have some
 429          * basic stuff in place.  Now search through the list for other shared
 430          * libraries that should be loaded, and insert them on the list in the
 431          * correct order.
 432          */
 433
 434         _dl_map_cache();
 435
 436         if (_dl_preload) {
 437                 char c, *str, *str2;
 438
 439                 str = _dl_preload;
 440                 while (*str == ':' || *str == ' ' || *str == '\t')
 441                         str++;
 442
 443                 while (*str) {
 444                         str2 = str;
 445                         while (*str2 && *str2 != ':' && *str2 != ' ' && *str2 != '\t')
 446                                 str2++;
 447                         c = *str2;
 448                         *str2 = '\0';
 449
 450                         if (!_dl_secure || _dl_strchr(str, '/') == NULL) {
 451                                 _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", str, _dl_progname);
 452
 453                                 tpnt1 = _dl_load_shared_library(_dl_secure, &rpnt, NULL, str, trace_loaded_objects);
 454                                 if (!tpnt1) {
 455 #ifdef __LDSO_LDD_SUPPORT__
 456                                         if (trace_loaded_objects)
 457                                                 _dl_dprintf(1, "\t%s => not found\n", str);
 458                                         else
 459 #endif
 460                                         {
 461                                                 _dl_dprintf(2, "%s: can't load " "library '%s'\n", _dl_progname, str);
 462                                                 _dl_exit(15);
 463                                         }
 464                                 } else {
 465                                         tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 466
 467                                         _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
 468
 469 #ifdef __LDSO_LDD_SUPPORT__
 470                                         if (trace_loaded_objects &&
 471                                             tpnt1->usage_count == 1) {
 472                                                 /* This is a real hack to make
 473                                                  * ldd not print the library
 474                                                  * itself when run on a
 475                                                  * library.
 476                                                  */
 477                                                 if (_dl_strcmp(_dl_progname, str) != 0)
 478                                                         _dl_dprintf(1, "\t%s => %s (%x)\n", str, tpnt1->libname,
 479                                                                     DL_LOADADDR_BASE(tpnt1->loadaddr));
 480                                         }
 481 #endif
 482                                 }
 483                         }
 484
 485                         *str2 = c;
 486                         str = str2;
 487                         while (*str == ':' || *str == ' ' || *str == '\t')
 488                                 str++;
 489                 }
 490         }
 491
 492 #ifdef __LDSO_PRELOAD_FILE_SUPPORT__
 493         do {
 494                 struct stat st;
 495                 char *preload;
 496                 int fd;
 497                 char c, *cp, *cp2;
 498
 499                 if (_dl_stat(LDSO_PRELOAD, &st) || st.st_size == 0) {
 500                         break;
 501                 }
 502
 503                 if ((fd = _dl_open(LDSO_PRELOAD, O_RDONLY, 0)) < 0) {
 504                         _dl_dprintf(2, "%s: can't open file '%s'\n",
 505                                     _dl_progname, LDSO_PRELOAD);
 506                         break;
 507                 }
 508
 509                 preload = (caddr_t) _dl_mmap(0, st.st_size + 1,
 510                                              PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 511                 _dl_close(fd);
 512                 if (preload == (caddr_t) -1) {
 513                         _dl_dprintf(2, "%s:%i: can't map '%s'\n",
 514                                     _dl_progname, __LINE__, LDSO_PRELOAD);
 515                         break;
 516                 }
 517
 518                 /* convert all separators and comments to spaces */
 519                 for (cp = preload; *cp; /*nada */ ) {
 520                         if (*cp == ':' || *cp == '\t' || *cp == '\n') {
 521                                 *cp++ = ' ';
 522                         } else if (*cp == '#') {
 523                                 do {
 524                                         *cp++ = ' ';
 525                                 } while (*cp != '\n' && *cp != '\0');
 526                         } else {
 527                                 cp++;
 528                         }
 529                 }
 530
 531                 /* find start of first library */
 532                 for (cp = preload; *cp && *cp == ' '; cp++)
 533                         /*nada */ ;
 534
 535                 while (*cp) {
 536                         /* find end of library */
 537                         for (cp2 = cp; *cp && *cp != ' '; cp++)
 538                                 /*nada */ ;
 539                         c = *cp;
 540                         *cp = '\0';
 541
 542                         _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", cp2, _dl_progname);
 543
 544                         tpnt1 = _dl_load_shared_library(0, &rpnt, NULL, cp2, trace_loaded_objects);
 545                         if (!tpnt1) {
 546 #ifdef __LDSO_LDD_SUPPORT__
 547                                 if (trace_loaded_objects)
 548                                         _dl_dprintf(1, "\t%s => not found\n", cp2);
 549                                 else
 550 #endif
 551                                 {
 552                                         _dl_dprintf(2, "%s: can't load library '%s'\n", _dl_progname, cp2);
 553                                         _dl_exit(15);
 554                                 }
 555                         } else {
 556                                 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 557
 558                                 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
 559
 560 #ifdef __LDSO_LDD_SUPPORT__
 561                                 if (trace_loaded_objects &&
 562                                     tpnt1->usage_count == 1) {
 563                                         _dl_dprintf(1, "\t%s => %s (%x)\n",
 564                                                     cp2, tpnt1->libname,
 565                                                     DL_LOADADDR_BASE(tpnt1->loadaddr));
 566                                 }
 567 #endif
 568                         }
 569
 570                         /* find start of next library */
 571                         *cp = c;
 572                         for ( /*nada */ ; *cp && *cp == ' '; cp++)
 573                                 /*nada */ ;
 574                 }
 575
 576                 _dl_munmap(preload, st.st_size + 1);
 577         } while (0);
 578 #endif /* __LDSO_PRELOAD_FILE_SUPPORT__ */
 579
 580         nlist = 0;
 581         for (tcurr = _dl_loaded_modules; tcurr; tcurr = tcurr->next) {
 582                 ElfW(Dyn) *this_dpnt;
 583
 584                 nlist++;
 585                 for (this_dpnt = (ElfW(Dyn) *) tcurr->dynamic_addr; this_dpnt->d_tag; this_dpnt++) {
 586                         if (this_dpnt->d_tag == DT_NEEDED) {
 587                                 char *name;
 588                                 struct init_fini_list *tmp;
 589
 590                                 lpntstr = (char*) (tcurr->dynamic_info[DT_STRTAB] + this_dpnt->d_un.d_val);
 591                                 name = _dl_get_last_path_component(lpntstr);
 592                                 if (_dl_strcmp(name, UCLIBC_LDSO) == 0)
 593                                         continue;
 594
 595                                 _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", lpntstr, _dl_progname);
 596
 597                                 if (!(tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, trace_loaded_objects))) {
 598 #ifdef __LDSO_LDD_SUPPORT__
 599                                         if (trace_loaded_objects) {
 600                                                 _dl_dprintf(1, "\t%s => not found\n", lpntstr);
 601                                                 continue;
 602                                         } else
 603 #endif
 604                                         {
 605                                                 _dl_dprintf(2, "%s: can't load library '%s'\n", _dl_progname, lpntstr);
 606                                                 _dl_exit(16);
 607                                         }
 608                                 }
 609
 610                                 tmp = alloca(sizeof(struct init_fini_list)); /* Allocates on stack, no need to free this memory */
 611                                 tmp->tpnt = tpnt1;
 612                                 tmp->next = tcurr->init_fini;
 613                                 tcurr->init_fini = tmp;
 614
 615                                 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 616
 617                                 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
 618
 619 #ifdef __LDSO_LDD_SUPPORT__
 620                                 if (trace_loaded_objects &&
 621                                     tpnt1->usage_count == 1) {
 622                                         _dl_dprintf(1, "\t%s => %s (%x)\n",
 623                                                     lpntstr, tpnt1->libname,
 624                                                     DL_LOADADDR_BASE(tpnt1->loadaddr));
 625                                 }
 626 #endif
 627                         }
 628                 }
 629         }
 630         _dl_unmap_cache();
 631
 632         --nlist; /* Exclude the application. */
 633         init_fini_list = _dl_malloc(nlist * sizeof(struct elf_resolve *));
 634         i = 0;
 635         for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
 636                 init_fini_list[i++] = tcurr;
 637         }
 638
 639         /* Sort the INIT/FINI list in dependency order. */
 640         for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
 641                 int j, k;
 642
 643                 for (j = 0; init_fini_list[j] != tcurr; ++j)
 644                         /* Empty */;
 645                 for (k = j + 1; k < nlist; ++k) {
 646                         struct init_fini_list *runp = init_fini_list[k]->init_fini;
 647
 648                         for (; runp; runp = runp->next) {
 649                                 if (runp->tpnt == tcurr) {
 650                                         struct elf_resolve *here = init_fini_list[k];
 651                                         _dl_if_debug_dprint("Move %s from pos %d to %d in INIT/FINI list\n", here->libname, k, j);
 652                                         for (i = (k - j); i; --i)
 653                                                 init_fini_list[i+j] = init_fini_list[i+j-1];
 654                                         init_fini_list[j] = here;
 655                                         ++j;
 656                                         break;
 657                                 }
 658                         }
 659                 }
 660         }
 661 #ifdef __SUPPORT_LD_DEBUG__
 662         if (_dl_debug) {
 663                 _dl_dprintf(_dl_debug_file, "\nINIT/FINI order and dependencies:\n");
 664                 for (i = 0; i < nlist; i++) {
 665                         struct init_fini_list *tmp;
 666
 667                         _dl_dprintf(_dl_debug_file, "lib: %s has deps:\n",
 668                                     init_fini_list[i]->libname);
 669                         tmp = init_fini_list[i]->init_fini;
 670                         for (; tmp; tmp = tmp->next)
 671                                 _dl_dprintf(_dl_debug_file, " %s ", tmp->tpnt->libname);
 672                         _dl_dprintf(_dl_debug_file, "\n");
 673                 }
 674         }
 675 #endif
 676
 677         /*
 678          * If the program interpreter is not in the module chain, add it.
 679          * This will be required for dlopen to be able to access the internal
 680          * functions in the dynamic linker and to relocate the interpreter
 681          * again once all libs are loaded.
 682          */
 683         if (tpnt) {
 684                 ElfW(Ehdr) *epnt = (ElfW(Ehdr) *) auxvt[AT_BASE].a_un.a_val;
 685                 ElfW(Phdr) *myppnt = (ElfW(Phdr) *) DL_RELOC_ADDR(load_addr, epnt->e_phoff);
 686                 int j;
 687
 688                 tpnt = _dl_add_elf_hash_table(tpnt->libname, load_addr,
 689                                               tpnt->dynamic_info,
 690                                               (unsigned long)tpnt->dynamic_addr,
 691                                               0);
 692
 693                 if (_dl_stat(tpnt->libname, &st) >= 0) {
 694                         tpnt->st_dev = st.st_dev;
 695                         tpnt->st_ino = st.st_ino;
 696                 }
 697                 tpnt->n_phent = epnt->e_phnum;
 698                 tpnt->ppnt = myppnt;
 699                 for (j = 0; j < epnt->e_phnum; j++, myppnt++) {
 700                         if (myppnt->p_type ==  PT_GNU_RELRO) {
 701                                 tpnt->relro_addr = myppnt->p_vaddr;
 702                                 tpnt->relro_size = myppnt->p_memsz;
 703                                 break;
 704                         }
 705                 }
 706                 tpnt->libtype = program_interpreter;
 707                 tpnt->usage_count++;
 708                 tpnt->symbol_scope = _dl_symbol_tables;
 709                 if (rpnt) {
 710                         rpnt->next = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 711                         _dl_memset(rpnt->next, 0, sizeof(struct dyn_elf));
 712                         rpnt->next->prev = rpnt;
 713                         rpnt = rpnt->next;
 714                 } else {
 715                         rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 716                         _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
 717                 }
 718                 rpnt->dyn = tpnt;
 719                 tpnt->rtld_flags = RTLD_NOW | RTLD_GLOBAL; /* Must not be LAZY */
 720 #ifdef RERELOCATE_LDSO
 721                 /* Only rerelocate functions for now. */
 722                 tpnt->init_flag = RELOCS_DONE;
 723                 lpnt = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT]);
 724 # ifdef ALLOW_ZERO_PLTGOT
 725                 if (tpnt->dynamic_info[DT_PLTGOT])
 726 # endif
 727                         INIT_GOT(lpnt, tpnt);
 728 #else
 729                 tpnt->init_flag = RELOCS_DONE | JMP_RELOCS_DONE;
 730 #endif
 731                 tpnt = NULL;
 732         }
 733
 734 #ifdef __LDSO_LDD_SUPPORT__
 735         /* End of the line for ldd.... */
 736         if (trace_loaded_objects) {
 737                 _dl_dprintf(1, "\t%s => %s (%x)\n",
 738                             rpnt->dyn->libname + _dl_strlen(_dl_ldsopath) + 1,
 739                             rpnt->dyn->libname, DL_LOADADDR_BASE(rpnt->dyn->loadaddr));
 740                 _dl_exit(0);
 741         }
 742 #endif
 743
 744         _dl_debug_early("Beginning relocation fixups\n");
 745
 746 #ifdef __mips__
 747         /*
 748          * Relocation of the GOT entries for MIPS have to be done
 749          * after all the libraries have been loaded.
 750          */
 751         _dl_perform_mips_global_got_relocations(_dl_loaded_modules, !unlazy);
 752 #endif
 753
 754         /*
 755          * OK, now all of the kids are tucked into bed in their proper
 756          * addresses.  Now we go through and look for REL and RELA records that
 757          * indicate fixups to the GOT tables.  We need to do this in reverse
 758          * order so that COPY directives work correctly.
 759          */
 760         if (_dl_symbol_tables)
 761                 if (_dl_fixup(_dl_symbol_tables, unlazy))
 762                         _dl_exit(-1);
 763
 764         for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 765                 if (tpnt->relro_size)
 766                         _dl_protect_relro (tpnt);
 767         }
 768
 769         /* OK, at this point things are pretty much ready to run.  Now we need
 770          * to touch up a few items that are required, and then we can let the
 771          * user application have at it.  Note that the dynamic linker itself
 772          * is not guaranteed to be fully dynamicly linked if we are using
 773          * ld.so.1, so we have to look up each symbol individually.
 774          */
 775
 776         _dl_envp = (unsigned long *) (intptr_t) _dl_find_hash(__C_SYMBOL_PREFIX__ "__environ", _dl_symbol_tables, NULL, 0);
 777         if (_dl_envp)
 778                 *_dl_envp = (unsigned long) envp;
 779
 780 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
 781         {
 782                 unsigned int j;
 783                 ElfW(Phdr) *myppnt;
 784
 785                 /* We had to set the protections of all pages to R/W for
 786                  * dynamic linking.  Set text pages back to R/O.
 787                  */
 788                 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 789                         for (myppnt = tpnt->ppnt, j = 0; j < tpnt->n_phent; j++, myppnt++) {
 790                                 if (myppnt->p_type == PT_LOAD && !(myppnt->p_flags & PF_W) && tpnt->dynamic_info[DT_TEXTREL]) {
 791                                         _dl_mprotect((void *) (DL_RELOC_ADDR(tpnt->loadaddr, myppnt->p_vaddr) & PAGE_ALIGN),
 792                                                         (myppnt->p_vaddr & ADDR_ALIGN) + (unsigned long) myppnt->p_filesz, LXFLAGS(myppnt->p_flags));
 793                                 }
 794                         }
 795                 }
 796
 797         }
 798 #endif
 799         /* Notify the debugger we have added some objects. */
 800         _dl_debug_addr->r_state = RT_ADD;
 801         _dl_debug_state();
 802
 803         /* Run pre-initialization functions for the executable.  */
 804         _dl_run_array_forward(_dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAY],
 805                               _dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAYSZ],
 806                               _dl_loaded_modules->loadaddr);
 807
 808         /* Run initialization functions for loaded objects.  For the
 809            main executable, they will be run from __uClibc_main.  */
 810         for (i = nlist; i; --i) {
 811                 tpnt = init_fini_list[i-1];
 812                 tpnt->init_fini = NULL; /* Clear, since alloca was used */
 813                 if (tpnt->init_flag & INIT_FUNCS_CALLED)
 814                         continue;
 815                 tpnt->init_flag |= INIT_FUNCS_CALLED;
 816
 817                 if (tpnt->dynamic_info[DT_INIT]) {
 818                         void (*dl_elf_func) (void);
 819
 820                         dl_elf_func = (void (*)(void)) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_INIT]);
 821
 822                         _dl_if_debug_dprint("calling INIT: %s\n\n", tpnt->libname);
 823
 824                         DL_CALL_FUNC_AT_ADDR (dl_elf_func, tpnt->loadaddr, (void(*)(void)));
 825                 }
 826
 827                 _dl_run_init_array(tpnt);
 828         }
 829
 830         /* Find the real malloc function and make ldso functions use that from now on */
 831         _dl_malloc_function = (void* (*)(size_t)) (intptr_t) _dl_find_hash(__C_SYMBOL_PREFIX__ "malloc",
 832                         _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT);
 833
 834         /* Notify the debugger that all objects are now mapped in.  */
 835         _dl_debug_addr->r_state = RT_CONSISTENT;
 836         _dl_debug_state();
 837 }
 838
 839 char *_dl_getenv(const char *symbol, char **envp)
 840 {
 841         char *pnt;
 842         const char *pnt1;
 843
 844         while ((pnt = *envp++)) {
 845                 pnt1 = symbol;
 846                 while (*pnt && *pnt == *pnt1)
 847                         pnt1++, pnt++;
 848                 if (!*pnt || *pnt != '=' || *pnt1)
 849                         continue;
 850                 return pnt + 1;
 851         }
 852         return 0;
 853 }
 854
 855 void _dl_unsetenv(const char *symbol, char **envp)
 856 {
 857         char *pnt;
 858         const char *pnt1;
 859         char **newenvp = envp;
 860
 861         for (pnt = *envp; pnt; pnt = *++envp) {
 862                 pnt1 = symbol;
 863                 while (*pnt && *pnt == *pnt1)
 864                         pnt1++, pnt++;
 865                 if (!*pnt || *pnt != '=' || *pnt1)
 866                         *newenvp++ = *envp;
 867         }
 868         *newenvp++ = *envp;
 869         return;
 870 }
 871
 872 static int _dl_suid_ok(void)
 873 {
 874         __kernel_uid_t uid, euid;
 875         __kernel_gid_t gid, egid;
 876
 877         uid = _dl_getuid();
 878         euid = _dl_geteuid();
 879         gid = _dl_getgid();
 880         egid = _dl_getegid();
 881
 882         if (uid == euid && gid == egid) {
 883                 return 1;
 884         }
 885         return 0;
 886 }
 887
 888 void *_dl_malloc(size_t size)
 889 {
 890         void *retval;
 891
 892 #if 0
 893         _dl_debug_early("request for %d bytes\n", size);
 894 #endif
 895
 896         if (_dl_malloc_function)
 897                 return (*_dl_malloc_function) (size);
 898
 899         if (_dl_malloc_addr - _dl_mmap_zero + size > _dl_pagesize) {
 900                 size_t rounded_size;
 901
 902                 /* Since the above assumes we get a full page even if
 903                    we request less than that, make sure we request a
 904                    full page, since uClinux may give us less than than
 905                    a full page.  We might round even
 906                    larger-than-a-page sizes, but we end up never
 907                    reusing _dl_mmap_zero/_dl_malloc_addr in that case,
 908                    so we don't do it.
 909
 910                    The actual page size doesn't really matter; as long
 911                    as we're self-consistent here, we're safe.  */
 912                 if (size < _dl_pagesize)
 913                         rounded_size = (size + _dl_pagesize - 1) & _dl_pagesize;
 914                 else
 915                         rounded_size = size;
 916
 917                 _dl_debug_early("mmapping more memory\n");
 918                 _dl_mmap_zero = _dl_malloc_addr = _dl_mmap((void *) 0, rounded_size,
 919                                 PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 920                 if (_dl_mmap_check_error(_dl_mmap_zero)) {
 921                         _dl_dprintf(2, "%s: mmap of a spare page failed!\n", _dl_progname);
 922                         _dl_exit(20);
 923                 }
 924         }
 925         retval = _dl_malloc_addr;
 926         _dl_malloc_addr += size;
 927
 928         /*
 929          * Align memory to DL_MALLOC_ALIGN byte boundary.  Some
 930          * platforms require this, others simply get better
 931          * performance.
 932          */
 933         _dl_malloc_addr = (unsigned char *) (((unsigned long) _dl_malloc_addr + DL_MALLOC_ALIGN - 1) & ~(DL_MALLOC_ALIGN - 1));
 934         return retval;
 935 }
 936
 937 void _dl_free (void *p)
 938 {
 939         if (_dl_free_function)
 940                 (*_dl_free_function) (p);
 941 }
 942
 943 #include "dl-hash.c"
 944 #include "dl-elf.c"