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                           DL_GET_READY_TO_RUN_EXTRA_PARMS)
 137 {
 138         ElfW(Addr) app_mapaddr = 0;
 139         ElfW(Phdr) *ppnt;
 140         ElfW(Dyn) *dpnt;
 141         char *lpntstr;
 142         unsigned int i;
 143         int unlazy = 0, trace_loaded_objects = 0;
 144         struct dyn_elf *rpnt;
 145         struct elf_resolve *tcurr;
 146         struct elf_resolve *tpnt1;
 147         struct elf_resolve app_tpnt_tmp;
 148         struct elf_resolve *app_tpnt = &app_tpnt_tmp;
 149         struct r_debug *debug_addr;
 150         unsigned long *lpnt;
 151         unsigned long *_dl_envp;                /* The environment address */
 152         ElfW(Addr) relro_addr = 0;
 153         size_t relro_size = 0;
 154         struct stat st;
 155
 156         /* Wahoo!!! We managed to make a function call!  Get malloc
 157          * setup so we can use _dl_dprintf() to print debug noise
 158          * instead of the SEND_STDERR macros used in dl-startup.c */
 159
 160         _dl_memset(app_tpnt, 0x00, sizeof(*app_tpnt));
 161
 162         /* Store the page size for later use */
 163         _dl_pagesize = (auxvt[AT_PAGESZ].a_un.a_val) ? (size_t) auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
 164         /* Make it so _dl_malloc can use the page of memory we have already
 165          * allocated.  We shouldn't need to grab any more memory.  This must
 166          * be first since things like _dl_dprintf() use _dl_malloc()...
 167          */
 168         _dl_malloc_addr = (unsigned char *)_dl_pagesize;
 169         _dl_mmap_zero = 0;
 170
 171         /* Wahoo!!! */
 172         _dl_debug_early("Cool, ldso survived making function calls\n");
 173
 174         /* Now we have done the mandatory linking of some things.  We are now
 175          * free to start using global variables, since these things have all
 176          * been fixed up by now.  Still no function calls outside of this
 177          * library, since the dynamic resolver is not yet ready.
 178          */
 179         if (argv[0]) {
 180                 _dl_progname = argv[0];
 181         }
 182
 183         if (_start == (void *) auxvt[AT_ENTRY].a_un.a_val) {
 184                 _dl_dprintf(_dl_debug_file, "Standalone execution is not supported yet\n");
 185                 _dl_exit(1);
 186         }
 187
 188         /* Start to build the tables of the modules that are required for
 189          * this beast to run.  We start with the basic executable, and then
 190          * go from there.  Eventually we will run across ourself, and we
 191          * will need to properly deal with that as well.
 192          */
 193         rpnt = NULL;
 194         if (_dl_getenv("LD_BIND_NOW", envp))
 195                 unlazy = RTLD_NOW;
 196
 197         /* Now we need to figure out what kind of options are selected.
 198          * Note that for SUID programs we ignore the settings in
 199          * LD_LIBRARY_PATH.
 200          */
 201         if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && _dl_suid_ok()) ||
 202             (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
 203              auxvt[AT_UID].a_un.a_val == auxvt[AT_EUID].a_un.a_val &&
 204              auxvt[AT_GID].a_un.a_val == auxvt[AT_EGID].a_un.a_val)) {
 205                 _dl_secure = 0;
 206                 _dl_preload = _dl_getenv("LD_PRELOAD", envp);
 207                 _dl_library_path = _dl_getenv("LD_LIBRARY_PATH", envp);
 208         } else {
 209                 static const char unsecure_envvars[] =
 210 #ifdef EXTRA_UNSECURE_ENVVARS
 211                         EXTRA_UNSECURE_ENVVARS
 212 #endif
 213                         UNSECURE_ENVVARS;
 214                 const char *nextp;
 215                 _dl_secure = 1;
 216
 217                 nextp = unsecure_envvars;
 218                 do {
 219                         _dl_unsetenv (nextp, envp);
 220                         /* We could use rawmemchr but this need not be fast.  */
 221                         nextp = (char *) _dl_strchr(nextp, '\0') + 1;
 222                 } while (*nextp != '\0');
 223                 _dl_preload = NULL;
 224                 _dl_library_path = NULL;
 225                 /* SUID binaries can be exploited if they do LAZY relocation. */
 226                 unlazy = RTLD_NOW;
 227         }
 228
 229         /* sjhill: your TLS init should go before this */
 230 #ifdef __UCLIBC_HAS_SSP__
 231         /* Set up the stack checker's canary.  */
 232         stack_chk_guard = _dl_setup_stack_chk_guard ();
 233 # ifdef THREAD_SET_STACK_GUARD
 234         THREAD_SET_STACK_GUARD (stack_chk_guard);
 235 #  ifdef __UCLIBC_HAS_SSP_COMPAT__
 236         __guard = stack_chk_guard;
 237 #  endif
 238 # else
 239         __stack_chk_guard = stack_chk_guard;
 240 # endif
 241 #endif
 242
 243         /* At this point we are now free to examine the user application,
 244          * and figure out which libraries are supposed to be called.  Until
 245          * we have this list, we will not be completely ready for dynamic
 246          * linking.
 247          */
 248
 249         /* Find the runtime load address of the main executable.  This may be
 250          * different from what the ELF header says for ET_DYN/PIE executables.
 251          */
 252         {
 253                 unsigned int idx;
 254                 ElfW(Phdr) *phdr = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 255
 256                 for (idx = 0; idx < auxvt[AT_PHNUM].a_un.a_val; idx++, phdr++)
 257                         if (phdr->p_type == PT_PHDR) {
 258                                 DL_INIT_LOADADDR_PROG(app_tpnt->loadaddr, auxvt[AT_PHDR].a_un.a_val - phdr->p_vaddr);
 259                                 break;
 260                         }
 261
 262                 if (DL_LOADADDR_BASE(app_tpnt->loadaddr))
 263                         _dl_debug_early("Position Independent Executable: "
 264                                         "app_tpnt->loadaddr=%x\n", DL_LOADADDR_BASE(app_tpnt->loadaddr));
 265         }
 266
 267         /*
 268          * This is used by gdb to locate the chain of shared libraries that are
 269          * currently loaded.
 270          */
 271         debug_addr = _dl_malloc(sizeof(struct r_debug));
 272         _dl_memset(debug_addr, 0, sizeof(struct r_debug));
 273
 274         ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 275         for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
 276                 if (ppnt->p_type == PT_GNU_RELRO) {
 277                         relro_addr = ppnt->p_vaddr;
 278                         relro_size = ppnt->p_memsz;
 279                 }
 280                 if (!app_mapaddr && (ppnt->p_type == PT_LOAD)) {
 281                         app_mapaddr = DL_RELOC_ADDR (app_tpnt->loadaddr, ppnt->p_vaddr);
 282                 }
 283                 if (ppnt->p_type == PT_DYNAMIC) {
 284                         dpnt = (ElfW(Dyn) *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
 285                         _dl_parse_dynamic_info(dpnt, app_tpnt->dynamic_info, debug_addr, app_tpnt->loadaddr);
 286 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
 287                         /* Ugly, ugly.  We need to call mprotect to change the
 288                          * protection of the text pages so that we can do the
 289                          * dynamic linking.  We can set the protection back
 290                          * again once we are done.
 291                          */
 292                         _dl_debug_early("calling mprotect on the application program\n");
 293                         /* Now cover the application program. */
 294                         if (app_tpnt->dynamic_info[DT_TEXTREL]) {
 295                                 ElfW(Phdr) *ppnt_outer = ppnt;
 296                                 ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 297                                 for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
 298                                         if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
 299                                                 _dl_mprotect((void *) (DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr) & PAGE_ALIGN),
 300                                                              ((ppnt->p_vaddr + app_tpnt->loadaddr) & ADDR_ALIGN) +
 301                                                              (unsigned long) ppnt->p_filesz,
 302                                                              PROT_READ | PROT_WRITE | PROT_EXEC);
 303                                 }
 304                                 ppnt = ppnt_outer;
 305                         }
 306 #else
 307                         if (app_tpnt->dynamic_info[DT_TEXTREL]) {
 308                                 _dl_dprintf(_dl_debug_file, "Can't modify application's text section; use the GCC option -fPIE for position-independent executables.\n");
 309                                 _dl_exit(1);
 310                         }
 311 #endif
 312
 313 #ifndef ALLOW_ZERO_PLTGOT
 314                         /* make sure it's really there. */
 315                         if (app_tpnt->dynamic_info[DT_PLTGOT] == 0)
 316                                 continue;
 317 #endif
 318                         /* OK, we have what we need - slip this one into the list. */
 319                         app_tpnt = _dl_add_elf_hash_table(_dl_progname, app_tpnt->loadaddr,
 320                                         app_tpnt->dynamic_info,
 321                                         (unsigned long) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr),
 322                                         ppnt->p_filesz);
 323                         _dl_loaded_modules->libtype = elf_executable;
 324                         _dl_loaded_modules->ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
 325                         _dl_loaded_modules->n_phent = auxvt[AT_PHNUM].a_un.a_val;
 326                         _dl_symbol_tables = rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 327                         _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
 328                         rpnt->dyn = _dl_loaded_modules;
 329                         app_tpnt->mapaddr = app_mapaddr;
 330                         app_tpnt->rtld_flags = unlazy | RTLD_GLOBAL;
 331                         app_tpnt->usage_count++;
 332                         app_tpnt->symbol_scope = _dl_symbol_tables;
 333                         lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT]);
 334 #ifdef ALLOW_ZERO_PLTGOT
 335                         if (lpnt)
 336 #endif
 337                                 INIT_GOT(lpnt, _dl_loaded_modules);
 338                 }
 339
 340                 /* OK, fill this in - we did not have this before */
 341                 if (ppnt->p_type == PT_INTERP) {
 342                         char *ptmp;
 343
 344                         tpnt->libname = (char *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
 345
 346                         /* Store the path where the shared lib loader was found
 347                          * for later use
 348                          */
 349                         _dl_ldsopath = _dl_strdup(tpnt->libname);
 350                         ptmp = _dl_strrchr(_dl_ldsopath, '/');
 351                         if (ptmp != _dl_ldsopath)
 352                                 *ptmp = '\0';
 353
 354                         _dl_debug_early("Lib Loader: (%x) %s\n", (unsigned) DL_LOADADDR_BASE(tpnt->loadaddr), tpnt->libname);
 355                 }
 356         }
 357         app_tpnt->relro_addr = relro_addr;
 358         app_tpnt->relro_size = relro_size;
 359
 360 #ifdef __SUPPORT_LD_DEBUG__
 361         _dl_debug = _dl_getenv("LD_DEBUG", envp);
 362         if (_dl_debug) {
 363                 if (_dl_strstr(_dl_debug, "all")) {
 364                         _dl_debug_detail = _dl_debug_move = _dl_debug_symbols
 365                                 = _dl_debug_reloc = _dl_debug_bindings = _dl_debug_nofixups = (void*)1;
 366                 } else {
 367                         _dl_debug_detail   = _dl_strstr(_dl_debug, "detail");
 368                         _dl_debug_move     = _dl_strstr(_dl_debug, "move");
 369                         _dl_debug_symbols  = _dl_strstr(_dl_debug, "sym");
 370                         _dl_debug_reloc    = _dl_strstr(_dl_debug, "reloc");
 371                         _dl_debug_nofixups = _dl_strstr(_dl_debug, "nofix");
 372                         _dl_debug_bindings = _dl_strstr(_dl_debug, "bind");
 373                 }
 374         }
 375
 376         {
 377                 const char *dl_debug_output;
 378
 379                 dl_debug_output = _dl_getenv("LD_DEBUG_OUTPUT", envp);
 380
 381                 if (dl_debug_output) {
 382                         char tmp[22], *tmp1, *filename;
 383                         int len1, len2;
 384
 385                         _dl_memset(tmp, 0, sizeof(tmp));
 386                         tmp1 = _dl_simple_ltoa( tmp, (unsigned long)_dl_getpid());
 387
 388                         len1 = _dl_strlen(dl_debug_output);
 389                         len2 = _dl_strlen(tmp1);
 390
 391                         filename = _dl_malloc(len1+len2+2);
 392
 393                         if (filename) {
 394                                 _dl_strcpy (filename, dl_debug_output);
 395                                 filename[len1] = '.';
 396                                 _dl_strcpy (&filename[len1+1], tmp1);
 397
 398                                 _dl_debug_file= _dl_open(filename, O_WRONLY|O_CREAT, 0644);
 399                                 if (_dl_debug_file < 0) {
 400                                         _dl_debug_file = 2;
 401                                         _dl_dprintf(_dl_debug_file, "can't open file: '%s'\n",filename);
 402                                 }
 403                         }
 404                 }
 405         }
 406 #endif
 407
 408         if (_dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL) {
 409                 trace_loaded_objects++;
 410         }
 411
 412 #ifndef __LDSO_LDD_SUPPORT__
 413         if (trace_loaded_objects) {
 414                 _dl_dprintf(_dl_debug_file, "Use the ldd provided by uClibc\n");
 415                 _dl_exit(1);
 416         }
 417 #endif
 418
 419         /*
 420          * OK, fix one more thing - set up debug_addr so it will point
 421          * to our chain.  Later we may need to fill in more fields, but this
 422          * should be enough for now.
 423          */
 424         debug_addr->r_map = (struct link_map *) _dl_loaded_modules;
 425         debug_addr->r_version = 1;
 426         debug_addr->r_ldbase = DL_LOADADDR_BASE(load_addr);
 427         debug_addr->r_brk = (unsigned long) &_dl_debug_state;
 428         _dl_debug_addr = debug_addr;
 429
 430         /* Do notify the debugger untile the interpreter is in the list */
 431
 432         /* OK, we now have the application in the list, and we have some
 433          * basic stuff in place.  Now search through the list for other shared
 434          * libraries that should be loaded, and insert them on the list in the
 435          * correct order.
 436          */
 437
 438         _dl_map_cache();
 439
 440         if (_dl_preload) {
 441                 char c, *str, *str2;
 442
 443                 str = _dl_preload;
 444                 while (*str == ':' || *str == ' ' || *str == '\t')
 445                         str++;
 446
 447                 while (*str) {
 448                         str2 = str;
 449                         while (*str2 && *str2 != ':' && *str2 != ' ' && *str2 != '\t')
 450                                 str2++;
 451                         c = *str2;
 452                         *str2 = '\0';
 453
 454                         if (!_dl_secure || _dl_strchr(str, '/') == NULL) {
 455                                 _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", str, _dl_progname);
 456
 457                                 tpnt1 = _dl_load_shared_library(_dl_secure, &rpnt, NULL, str, trace_loaded_objects);
 458                                 if (!tpnt1) {
 459 #ifdef __LDSO_LDD_SUPPORT__
 460                                         if (trace_loaded_objects)
 461                                                 _dl_dprintf(1, "\t%s => not found\n", str);
 462                                         else
 463 #endif
 464                                         {
 465                                                 _dl_dprintf(2, "%s: can't load " "library '%s'\n", _dl_progname, str);
 466                                                 _dl_exit(15);
 467                                         }
 468                                 } else {
 469                                         tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 470
 471                                         _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
 472
 473 #ifdef __LDSO_LDD_SUPPORT__
 474                                         if (trace_loaded_objects &&
 475                                             tpnt1->usage_count == 1) {
 476                                                 /* This is a real hack to make
 477                                                  * ldd not print the library
 478                                                  * itself when run on a
 479                                                  * library.
 480                                                  */
 481                                                 if (_dl_strcmp(_dl_progname, str) != 0)
 482                                                         _dl_dprintf(1, "\t%s => %s (%x)\n", str, tpnt1->libname,
 483                                                                     DL_LOADADDR_BASE(tpnt1->loadaddr));
 484                                         }
 485 #endif
 486                                 }
 487                         }
 488
 489                         *str2 = c;
 490                         str = str2;
 491                         while (*str == ':' || *str == ' ' || *str == '\t')
 492                                 str++;
 493                 }
 494         }
 495
 496 #ifdef __LDSO_PRELOAD_FILE_SUPPORT__
 497         do {
 498                 struct stat st;
 499                 char *preload;
 500                 int fd;
 501                 char c, *cp, *cp2;
 502
 503                 if (_dl_stat(LDSO_PRELOAD, &st) || st.st_size == 0) {
 504                         break;
 505                 }
 506
 507                 if ((fd = _dl_open(LDSO_PRELOAD, O_RDONLY, 0)) < 0) {
 508                         _dl_dprintf(2, "%s: can't open file '%s'\n",
 509                                     _dl_progname, LDSO_PRELOAD);
 510                         break;
 511                 }
 512
 513                 preload = (caddr_t) _dl_mmap(0, st.st_size + 1,
 514                                              PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 515                 _dl_close(fd);
 516                 if (preload == (caddr_t) -1) {
 517                         _dl_dprintf(2, "%s:%i: can't map '%s'\n",
 518                                     _dl_progname, __LINE__, LDSO_PRELOAD);
 519                         break;
 520                 }
 521
 522                 /* convert all separators and comments to spaces */
 523                 for (cp = preload; *cp; /*nada */ ) {
 524                         if (*cp == ':' || *cp == '\t' || *cp == '\n') {
 525                                 *cp++ = ' ';
 526                         } else if (*cp == '#') {
 527                                 do {
 528                                         *cp++ = ' ';
 529                                 } while (*cp != '\n' && *cp != '\0');
 530                         } else {
 531                                 cp++;
 532                         }
 533                 }
 534
 535                 /* find start of first library */
 536                 for (cp = preload; *cp && *cp == ' '; cp++)
 537                         /*nada */ ;
 538
 539                 while (*cp) {
 540                         /* find end of library */
 541                         for (cp2 = cp; *cp && *cp != ' '; cp++)
 542                                 /*nada */ ;
 543                         c = *cp;
 544                         *cp = '\0';
 545
 546                         _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", cp2, _dl_progname);
 547
 548                         tpnt1 = _dl_load_shared_library(0, &rpnt, NULL, cp2, trace_loaded_objects);
 549                         if (!tpnt1) {
 550 #ifdef __LDSO_LDD_SUPPORT__
 551                                 if (trace_loaded_objects)
 552                                         _dl_dprintf(1, "\t%s => not found\n", cp2);
 553                                 else
 554 #endif
 555                                 {
 556                                         _dl_dprintf(2, "%s: can't load library '%s'\n", _dl_progname, cp2);
 557                                         _dl_exit(15);
 558                                 }
 559                         } else {
 560                                 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 561
 562                                 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
 563
 564 #ifdef __LDSO_LDD_SUPPORT__
 565                                 if (trace_loaded_objects &&
 566                                     tpnt1->usage_count == 1) {
 567                                         _dl_dprintf(1, "\t%s => %s (%x)\n",
 568                                                     cp2, tpnt1->libname,
 569                                                     DL_LOADADDR_BASE(tpnt1->loadaddr));
 570                                 }
 571 #endif
 572                         }
 573
 574                         /* find start of next library */
 575                         *cp = c;
 576                         for ( /*nada */ ; *cp && *cp == ' '; cp++)
 577                                 /*nada */ ;
 578                 }
 579
 580                 _dl_munmap(preload, st.st_size + 1);
 581         } while (0);
 582 #endif /* __LDSO_PRELOAD_FILE_SUPPORT__ */
 583
 584         nlist = 0;
 585         for (tcurr = _dl_loaded_modules; tcurr; tcurr = tcurr->next) {
 586                 ElfW(Dyn) *this_dpnt;
 587
 588                 nlist++;
 589                 for (this_dpnt = (ElfW(Dyn) *) tcurr->dynamic_addr; this_dpnt->d_tag; this_dpnt++) {
 590                         if (this_dpnt->d_tag == DT_NEEDED) {
 591                                 char *name;
 592                                 struct init_fini_list *tmp;
 593
 594                                 lpntstr = (char*) (tcurr->dynamic_info[DT_STRTAB] + this_dpnt->d_un.d_val);
 595                                 name = _dl_get_last_path_component(lpntstr);
 596                                 if (_dl_strcmp(name, UCLIBC_LDSO) == 0)
 597                                         continue;
 598
 599                                 _dl_if_debug_dprint("\tfile='%s';  needed by '%s'\n", lpntstr, _dl_progname);
 600
 601                                 if (!(tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, trace_loaded_objects))) {
 602 #ifdef __LDSO_LDD_SUPPORT__
 603                                         if (trace_loaded_objects) {
 604                                                 _dl_dprintf(1, "\t%s => not found\n", lpntstr);
 605                                                 continue;
 606                                         } else
 607 #endif
 608                                         {
 609                                                 _dl_dprintf(2, "%s: can't load library '%s'\n", _dl_progname, lpntstr);
 610                                                 _dl_exit(16);
 611                                         }
 612                                 }
 613
 614                                 tmp = alloca(sizeof(struct init_fini_list)); /* Allocates on stack, no need to free this memory */
 615                                 tmp->tpnt = tpnt1;
 616                                 tmp->next = tcurr->init_fini;
 617                                 tcurr->init_fini = tmp;
 618
 619                                 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
 620
 621                                 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
 622
 623 #ifdef __LDSO_LDD_SUPPORT__
 624                                 if (trace_loaded_objects &&
 625                                     tpnt1->usage_count == 1) {
 626                                         _dl_dprintf(1, "\t%s => %s (%x)\n",
 627                                                     lpntstr, tpnt1->libname,
 628                                                     DL_LOADADDR_BASE(tpnt1->loadaddr));
 629                                 }
 630 #endif
 631                         }
 632                 }
 633         }
 634         _dl_unmap_cache();
 635
 636         --nlist; /* Exclude the application. */
 637         init_fini_list = _dl_malloc(nlist * sizeof(struct elf_resolve *));
 638         i = 0;
 639         for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
 640                 init_fini_list[i++] = tcurr;
 641         }
 642
 643         /* Sort the INIT/FINI list in dependency order. */
 644         for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
 645                 int j, k;
 646
 647                 for (j = 0; init_fini_list[j] != tcurr; ++j)
 648                         /* Empty */;
 649                 for (k = j + 1; k < nlist; ++k) {
 650                         struct init_fini_list *runp = init_fini_list[k]->init_fini;
 651
 652                         for (; runp; runp = runp->next) {
 653                                 if (runp->tpnt == tcurr) {
 654                                         struct elf_resolve *here = init_fini_list[k];
 655                                         _dl_if_debug_dprint("Move %s from pos %d to %d in INIT/FINI list\n", here->libname, k, j);
 656                                         for (i = (k - j); i; --i)
 657                                                 init_fini_list[i+j] = init_fini_list[i+j-1];
 658                                         init_fini_list[j] = here;
 659                                         ++j;
 660                                         break;
 661                                 }
 662                         }
 663                 }
 664         }
 665 #ifdef __SUPPORT_LD_DEBUG__
 666         if (_dl_debug) {
 667                 _dl_dprintf(_dl_debug_file, "\nINIT/FINI order and dependencies:\n");
 668                 for (i = 0; i < nlist; i++) {
 669                         struct init_fini_list *tmp;
 670
 671                         _dl_dprintf(_dl_debug_file, "lib: %s has deps:\n",
 672                                     init_fini_list[i]->libname);
 673                         tmp = init_fini_list[i]->init_fini;
 674                         for (; tmp; tmp = tmp->next)
 675                                 _dl_dprintf(_dl_debug_file, " %s ", tmp->tpnt->libname);
 676                         _dl_dprintf(_dl_debug_file, "\n");
 677                 }
 678         }
 679 #endif
 680
 681         /*
 682          * If the program interpreter is not in the module chain, add it.
 683          * This will be required for dlopen to be able to access the internal
 684          * functions in the dynamic linker and to relocate the interpreter
 685          * again once all libs are loaded.
 686          */
 687         if (tpnt) {
 688                 ElfW(Ehdr) *epnt = (ElfW(Ehdr) *) auxvt[AT_BASE].a_un.a_val;
 689                 ElfW(Phdr) *myppnt = (ElfW(Phdr) *) DL_RELOC_ADDR(load_addr, epnt->e_phoff);
 690                 int j;
 691
 692                 tpnt = _dl_add_elf_hash_table(tpnt->libname, load_addr,
 693                                               tpnt->dynamic_info,
 694                                               (unsigned long)tpnt->dynamic_addr,
 695                                               0);
 696
 697                 if (_dl_stat(tpnt->libname, &st) >= 0) {
 698                         tpnt->st_dev = st.st_dev;
 699                         tpnt->st_ino = st.st_ino;
 700                 }
 701                 tpnt->n_phent = epnt->e_phnum;
 702                 tpnt->ppnt = myppnt;
 703                 for (j = 0; j < epnt->e_phnum; j++, myppnt++) {
 704                         if (myppnt->p_type ==  PT_GNU_RELRO) {
 705                                 tpnt->relro_addr = myppnt->p_vaddr;
 706                                 tpnt->relro_size = myppnt->p_memsz;
 707                                 break;
 708                         }
 709                 }
 710                 tpnt->libtype = program_interpreter;
 711                 tpnt->usage_count++;
 712                 tpnt->symbol_scope = _dl_symbol_tables;
 713                 if (rpnt) {
 714                         rpnt->next = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 715                         _dl_memset(rpnt->next, 0, sizeof(struct dyn_elf));
 716                         rpnt->next->prev = rpnt;
 717                         rpnt = rpnt->next;
 718                 } else {
 719                         rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
 720                         _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
 721                 }
 722                 rpnt->dyn = tpnt;
 723                 tpnt->rtld_flags = RTLD_NOW | RTLD_GLOBAL; /* Must not be LAZY */
 724 #ifdef RERELOCATE_LDSO
 725                 /* Only rerelocate functions for now. */
 726                 tpnt->init_flag = RELOCS_DONE;
 727                 lpnt = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT]);
 728 # ifdef ALLOW_ZERO_PLTGOT
 729                 if (tpnt->dynamic_info[DT_PLTGOT])
 730 # endif
 731                         INIT_GOT(lpnt, tpnt);
 732 #else
 733                 tpnt->init_flag = RELOCS_DONE | JMP_RELOCS_DONE;
 734 #endif
 735                 tpnt = NULL;
 736         }
 737
 738 #ifdef __LDSO_LDD_SUPPORT__
 739         /* End of the line for ldd.... */
 740         if (trace_loaded_objects) {
 741                 _dl_dprintf(1, "\t%s => %s (%x)\n",
 742                             rpnt->dyn->libname + _dl_strlen(_dl_ldsopath) + 1,
 743                             rpnt->dyn->libname, DL_LOADADDR_BASE(rpnt->dyn->loadaddr));
 744                 _dl_exit(0);
 745         }
 746 #endif
 747
 748         _dl_debug_early("Beginning relocation fixups\n");
 749
 750 #ifdef __mips__
 751         /*
 752          * Relocation of the GOT entries for MIPS have to be done
 753          * after all the libraries have been loaded.
 754          */
 755         _dl_perform_mips_global_got_relocations(_dl_loaded_modules, !unlazy);
 756 #endif
 757
 758         /*
 759          * OK, now all of the kids are tucked into bed in their proper
 760          * addresses.  Now we go through and look for REL and RELA records that
 761          * indicate fixups to the GOT tables.  We need to do this in reverse
 762          * order so that COPY directives work correctly.
 763          */
 764         if (_dl_symbol_tables)
 765                 if (_dl_fixup(_dl_symbol_tables, unlazy))
 766                         _dl_exit(-1);
 767
 768         for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 769                 if (tpnt->relro_size)
 770                         _dl_protect_relro (tpnt);
 771         }
 772
 773         /* OK, at this point things are pretty much ready to run.  Now we need
 774          * to touch up a few items that are required, and then we can let the
 775          * user application have at it.  Note that the dynamic linker itself
 776          * is not guaranteed to be fully dynamicly linked if we are using
 777          * ld.so.1, so we have to look up each symbol individually.
 778          */
 779
 780         _dl_envp = (unsigned long *) (intptr_t) _dl_find_hash(__C_SYMBOL_PREFIX__ "__environ", _dl_symbol_tables, NULL, 0);
 781         if (_dl_envp)
 782                 *_dl_envp = (unsigned long) envp;
 783
 784 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
 785         {
 786                 unsigned int j;
 787                 ElfW(Phdr) *myppnt;
 788
 789                 /* We had to set the protections of all pages to R/W for
 790                  * dynamic linking.  Set text pages back to R/O.
 791                  */
 792                 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
 793                         for (myppnt = tpnt->ppnt, j = 0; j < tpnt->n_phent; j++, myppnt++) {
 794                                 if (myppnt->p_type == PT_LOAD && !(myppnt->p_flags & PF_W) && tpnt->dynamic_info[DT_TEXTREL]) {
 795                                         _dl_mprotect((void *) (DL_RELOC_ADDR(tpnt->loadaddr, myppnt->p_vaddr) & PAGE_ALIGN),
 796                                                         (myppnt->p_vaddr & ADDR_ALIGN) + (unsigned long) myppnt->p_filesz, LXFLAGS(myppnt->p_flags));
 797                                 }
 798                         }
 799                 }
 800
 801         }
 802 #endif
 803         /* Notify the debugger we have added some objects. */
 804         _dl_debug_addr->r_state = RT_ADD;
 805         _dl_debug_state();
 806
 807         /* Run pre-initialization functions for the executable.  */
 808         _dl_run_array_forward(_dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAY],
 809                               _dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAYSZ],
 810                               _dl_loaded_modules->loadaddr);
 811
 812         /* Run initialization functions for loaded objects.  For the
 813            main executable, they will be run from __uClibc_main.  */
 814         for (i = nlist; i; --i) {
 815                 tpnt = init_fini_list[i-1];
 816                 tpnt->init_fini = NULL; /* Clear, since alloca was used */
 817                 if (tpnt->init_flag & INIT_FUNCS_CALLED)
 818                         continue;
 819                 tpnt->init_flag |= INIT_FUNCS_CALLED;
 820
 821                 if (tpnt->dynamic_info[DT_INIT]) {
 822                         void (*dl_elf_func) (void);
 823
 824                         dl_elf_func = (void (*)(void)) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_INIT]);
 825
 826                         _dl_if_debug_dprint("calling INIT: %s\n\n", tpnt->libname);
 827
 828                         DL_CALL_FUNC_AT_ADDR (dl_elf_func, tpnt->loadaddr, (void(*)(void)));
 829                 }
 830
 831                 _dl_run_init_array(tpnt);
 832         }
 833
 834         /* Find the real malloc function and make ldso functions use that from now on */
 835         _dl_malloc_function = (void* (*)(size_t)) (intptr_t) _dl_find_hash(__C_SYMBOL_PREFIX__ "malloc",
 836                         _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT);
 837
 838         /* Notify the debugger that all objects are now mapped in.  */
 839         _dl_debug_addr->r_state = RT_CONSISTENT;
 840         _dl_debug_state();
 841 }
 842
 843 char *_dl_getenv(const char *symbol, char **envp)
 844 {
 845         char *pnt;
 846         const char *pnt1;
 847
 848         while ((pnt = *envp++)) {
 849                 pnt1 = symbol;
 850                 while (*pnt && *pnt == *pnt1)
 851                         pnt1++, pnt++;
 852                 if (!*pnt || *pnt != '=' || *pnt1)
 853                         continue;
 854                 return pnt + 1;
 855         }
 856         return 0;
 857 }
 858
 859 void _dl_unsetenv(const char *symbol, char **envp)
 860 {
 861         char *pnt;
 862         const char *pnt1;
 863         char **newenvp = envp;
 864
 865         for (pnt = *envp; pnt; pnt = *++envp) {
 866                 pnt1 = symbol;
 867                 while (*pnt && *pnt == *pnt1)
 868                         pnt1++, pnt++;
 869                 if (!*pnt || *pnt != '=' || *pnt1)
 870                         *newenvp++ = *envp;
 871         }
 872         *newenvp++ = *envp;
 873         return;
 874 }
 875
 876 static int _dl_suid_ok(void)
 877 {
 878         __kernel_uid_t uid, euid;
 879         __kernel_gid_t gid, egid;
 880
 881         uid = _dl_getuid();
 882         euid = _dl_geteuid();
 883         gid = _dl_getgid();
 884         egid = _dl_getegid();
 885
 886         if (uid == euid && gid == egid) {
 887                 return 1;
 888         }
 889         return 0;
 890 }
 891
 892 void *_dl_malloc(size_t size)
 893 {
 894         void *retval;
 895
 896 #if 0
 897         _dl_debug_early("request for %d bytes\n", size);
 898 #endif
 899
 900         if (_dl_malloc_function)
 901                 return (*_dl_malloc_function) (size);
 902
 903         if (_dl_malloc_addr - _dl_mmap_zero + size > _dl_pagesize) {
 904                 size_t rounded_size;
 905
 906                 /* Since the above assumes we get a full page even if
 907                    we request less than that, make sure we request a
 908                    full page, since uClinux may give us less than than
 909                    a full page.  We might round even
 910                    larger-than-a-page sizes, but we end up never
 911                    reusing _dl_mmap_zero/_dl_malloc_addr in that case,
 912                    so we don't do it.
 913
 914                    The actual page size doesn't really matter; as long
 915                    as we're self-consistent here, we're safe.  */
 916                 if (size < _dl_pagesize)
 917                         rounded_size = (size + _dl_pagesize - 1) & _dl_pagesize;
 918                 else
 919                         rounded_size = size;
 920
 921                 _dl_debug_early("mmapping more memory\n");
 922                 _dl_mmap_zero = _dl_malloc_addr = _dl_mmap((void *) 0, rounded_size,
 923                                 PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 924                 if (_dl_mmap_check_error(_dl_mmap_zero)) {
 925                         _dl_dprintf(2, "%s: mmap of a spare page failed!\n", _dl_progname);
 926                         _dl_exit(20);
 927                 }
 928         }
 929         retval = _dl_malloc_addr;
 930         _dl_malloc_addr += size;
 931
 932         /*
 933          * Align memory to DL_MALLOC_ALIGN byte boundary.  Some
 934          * platforms require this, others simply get better
 935          * performance.
 936          */
 937         _dl_malloc_addr = (unsigned char *) (((unsigned long) _dl_malloc_addr + DL_MALLOC_ALIGN - 1) & ~(DL_MALLOC_ALIGN - 1));
 938         return retval;
 939 }
 940
 941 void _dl_free (void *p)
 942 {
 943         if (_dl_free_function)
 944                 (*_dl_free_function) (p);
 945 }
 946
 947 #include "dl-hash.c"
 948 #include "dl-elf.c"