1 /* vi: set sw=4 ts=4: */
3 * Program to load an ELF binary on a linux system, and run it
4 * after resolving ELF shared library symbols
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
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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
34 #include "unsecvars.h"
36 /* Pull in common debug code */
39 #define ALLOW_ZERO_PLTGOT
41 #if defined(USE_TLS) && USE_TLS
45 /* Pull in the value of _dl_progname */
46 #include LDSO_ELFINTERP
48 /* Global variables used within the shared library loader */
49 char *_dl_library_path = NULL; /* Where we look for libraries */
50 char *_dl_preload = NULL; /* Things to be loaded before the libs */
51 char *_dl_ldsopath = NULL; /* Location of the shared lib loader */
52 int _dl_errno = 0; /* We can't use the real errno in ldso */
53 size_t _dl_pagesize = 0; /* Store the page size for use later */
54 struct r_debug *_dl_debug_addr = NULL; /* Used to communicate with the gdb debugger */
55 void *(*_dl_malloc_function) (size_t size) = NULL;
56 void (*_dl_free_function) (void *p) = NULL;
58 static int _dl_secure = 1; /* Are we dealing with setuid stuff? */
60 #ifdef __SUPPORT_LD_DEBUG__
61 char *_dl_debug = NULL;
62 char *_dl_debug_symbols = NULL;
63 char *_dl_debug_move = NULL;
64 char *_dl_debug_reloc = NULL;
65 char *_dl_debug_detail = NULL;
66 char *_dl_debug_nofixups = NULL;
67 char *_dl_debug_bindings = NULL;
68 int _dl_debug_file = 2;
71 /* Needed for standalone execution. */
72 unsigned long attribute_hidden _dl_skip_args = 0;
73 const char *_dl_progname = UCLIBC_LDSO; /* The name of the executable being run */
74 #include "dl-startup.c"
75 #include "dl-symbols.c"
79 * This stub function is used by some debuggers. The idea is that they
80 * can set an internal breakpoint on it, so that we are notified when the
81 * address mapping is changed in some way.
83 void _dl_debug_state(void);
84 rtld_hidden_proto(_dl_debug_state, noinline);
85 void _dl_debug_state(void)
87 /* Make sure GCC doesn't recognize this function as pure, to avoid
88 * having the calls optimized away.
92 rtld_hidden_def(_dl_debug_state);
94 static unsigned char *_dl_malloc_addr = NULL; /* Lets _dl_malloc use the already allocated memory page */
95 static unsigned char *_dl_mmap_zero = NULL; /* Also used by _dl_malloc */
97 static struct elf_resolve **init_fini_list;
98 static unsigned int nlist; /* # items in init_fini_list */
99 extern void _start(void);
101 #ifdef __UCLIBC_HAS_SSP__
102 # include <dl-osinfo.h>
103 uintptr_t stack_chk_guard;
104 # ifndef THREAD_SET_STACK_GUARD
105 /* Only exported for architectures that don't store the stack guard canary
106 * in local thread area. */
107 uintptr_t __stack_chk_guard attribute_relro;
108 # ifdef __UCLIBC_HAS_SSP_COMPAT__
109 strong_alias(__stack_chk_guard,__guard)
111 # elif __UCLIBC_HAS_SSP_COMPAT__
112 uintptr_t __guard attribute_relro;
116 char *_dl_getenv(const char *symbol, char **envp)
121 while ((pnt = *envp++)) {
123 while (*pnt && *pnt == *pnt1)
125 if (!*pnt || *pnt != '=' || *pnt1)
132 void _dl_unsetenv(const char *symbol, char **envp)
136 char **newenvp = envp;
138 for (pnt = *envp; pnt; pnt = *++envp) {
140 while (*pnt && *pnt == *pnt1)
142 if (!*pnt || *pnt != '=' || *pnt1)
149 static int _dl_suid_ok(void)
151 __kernel_uid_t uid, euid;
152 __kernel_gid_t gid, egid;
155 euid = _dl_geteuid();
157 egid = _dl_getegid();
159 if (uid == euid && gid == egid) {
165 void *_dl_malloc(size_t size)
170 _dl_debug_early("request for %d bytes\n", size);
173 if (_dl_malloc_function)
174 return (*_dl_malloc_function) (size);
176 if (_dl_malloc_addr - _dl_mmap_zero + size > _dl_pagesize) {
179 /* Since the above assumes we get a full page even if
180 we request less than that, make sure we request a
181 full page, since uClinux may give us less than than
182 a full page. We might round even
183 larger-than-a-page sizes, but we end up never
184 reusing _dl_mmap_zero/_dl_malloc_addr in that case,
187 The actual page size doesn't really matter; as long
188 as we're self-consistent here, we're safe. */
189 if (size < _dl_pagesize)
190 rounded_size = (size + ADDR_ALIGN) & _dl_pagesize;
194 _dl_debug_early("mmapping more memory\n");
195 _dl_mmap_zero = _dl_malloc_addr = _dl_mmap((void *) 0, rounded_size,
196 PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_UNINITIALIZE, -1, 0);
197 if (_dl_mmap_check_error(_dl_mmap_zero)) {
198 _dl_dprintf(_dl_debug_file, "%s: mmap of a spare page failed!\n", _dl_progname);
202 retval = _dl_malloc_addr;
203 _dl_malloc_addr += size;
206 * Align memory to DL_MALLOC_ALIGN byte boundary. Some
207 * platforms require this, others simply get better
210 _dl_malloc_addr = (unsigned char *) (((unsigned long) _dl_malloc_addr + DL_MALLOC_ALIGN - 1) & ~(DL_MALLOC_ALIGN - 1));
214 static void *_dl_zalloc(size_t size)
216 void *p = _dl_malloc(size);
218 _dl_memset(p, 0, size);
222 void _dl_free(void *p)
224 if (_dl_free_function)
225 (*_dl_free_function) (p);
228 #if defined(USE_TLS) && USE_TLS
229 void *_dl_memalign(size_t __boundary, size_t __size)
236 if (_dl_memalign_function)
237 return (*_dl_memalign_function) (__boundary, __size);
239 while (rounded < __boundary) {
240 rounded = (1 << i++);
243 delta = (((size_t) _dl_malloc_addr + __size) & (rounded - 1));
245 if ((result = _dl_malloc(rounded - delta)) == NULL)
248 result = _dl_malloc(__size);
254 static void __attribute__ ((destructor)) __attribute_used__ _dl_fini(void)
257 struct elf_resolve * tpnt;
259 for (i = 0; i < nlist; ++i) {
260 tpnt = init_fini_list[i];
261 if (tpnt->init_flag & FINI_FUNCS_CALLED)
263 tpnt->init_flag |= FINI_FUNCS_CALLED;
264 _dl_run_fini_array(tpnt);
265 if (tpnt->dynamic_info[DT_FINI]) {
266 void (*dl_elf_func) (void);
268 dl_elf_func = (void (*)(void)) (intptr_t) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_FINI]);
269 _dl_if_debug_dprint("\ncalling FINI: %s\n\n", tpnt->libname);
270 DL_CALL_FUNC_AT_ADDR (dl_elf_func, tpnt->loadaddr, (void(*)(void)));
275 void _dl_get_ready_to_run(struct elf_resolve *tpnt, DL_LOADADDR_TYPE load_addr,
276 ElfW(auxv_t) auxvt[AT_EGID + 1], char **envp,
278 DL_GET_READY_TO_RUN_EXTRA_PARMS)
280 ElfW(Addr) app_mapaddr = 0;
285 int unlazy = 0, trace_loaded_objects = 0;
286 struct dyn_elf *rpnt;
287 struct elf_resolve *tcurr;
288 struct elf_resolve *tpnt1;
289 struct elf_resolve app_tpnt_tmp;
290 struct elf_resolve *app_tpnt = &app_tpnt_tmp;
291 struct r_debug *debug_addr;
293 unsigned long *_dl_envp; /* The environment address */
294 ElfW(Addr) relro_addr = 0;
295 size_t relro_size = 0;
297 #if defined(USE_TLS) && USE_TLS
301 /* Wahoo!!! We managed to make a function call! Get malloc
302 * setup so we can use _dl_dprintf() to print debug noise
303 * instead of the SEND_STDERR macros used in dl-startup.c */
305 _dl_memset(app_tpnt, 0, sizeof(*app_tpnt));
307 /* Store the page size for later use */
308 _dl_pagesize = (auxvt[AT_PAGESZ].a_un.a_val) ? (size_t) auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
309 /* Make it so _dl_malloc can use the page of memory we have already
310 * allocated. We shouldn't need to grab any more memory. This must
311 * be first since things like _dl_dprintf() use _dl_malloc()...
313 _dl_malloc_addr = (unsigned char *)_dl_pagesize;
317 _dl_debug_early("Cool, ldso survived making function calls\n");
319 /* Now we have done the mandatory linking of some things. We are now
320 * free to start using global variables, since these things have all
321 * been fixed up by now. Still no function calls outside of this
322 * library, since the dynamic resolver is not yet ready.
325 _dl_progname = argv[0];
328 if (_start == (void *) auxvt[AT_ENTRY].a_un.a_val) {
329 _dl_dprintf(_dl_debug_file, "Standalone execution is not supported yet\n");
333 /* Start to build the tables of the modules that are required for
334 * this beast to run. We start with the basic executable, and then
335 * go from there. Eventually we will run across ourself, and we
336 * will need to properly deal with that as well.
339 if (_dl_getenv("LD_BIND_NOW", envp))
342 /* Now we need to figure out what kind of options are selected.
343 * Note that for SUID programs we ignore the settings in
346 if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && _dl_suid_ok()) ||
347 (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
348 auxvt[AT_UID].a_un.a_val == auxvt[AT_EUID].a_un.a_val &&
349 auxvt[AT_GID].a_un.a_val == auxvt[AT_EGID].a_un.a_val)) {
351 _dl_preload = _dl_getenv("LD_PRELOAD", envp);
352 _dl_library_path = _dl_getenv("LD_LIBRARY_PATH", envp);
354 static const char unsecure_envvars[] =
355 #ifdef EXTRA_UNSECURE_ENVVARS
356 EXTRA_UNSECURE_ENVVARS
362 nextp = unsecure_envvars;
364 _dl_unsetenv (nextp, envp);
365 /* We could use rawmemchr but this need not be fast. */
366 nextp = _dl_strchr(nextp, '\0') + 1;
367 } while (*nextp != '\0');
369 _dl_library_path = NULL;
370 /* SUID binaries can be exploited if they do LAZY relocation. */
374 #if defined(USE_TLS) && USE_TLS
375 _dl_error_catch_tsd = &_dl_initial_error_catch_tsd;
376 _dl_init_static_tls = &_dl_nothread_init_static_tls;
379 /* At this point we are now free to examine the user application,
380 * and figure out which libraries are supposed to be called. Until
381 * we have this list, we will not be completely ready for dynamic
385 /* Find the runtime load address of the main executable. This may be
386 * different from what the ELF header says for ET_DYN/PIE executables.
390 ElfW(Phdr) *phdr = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
392 for (idx = 0; idx < auxvt[AT_PHNUM].a_un.a_val; idx++, phdr++)
393 if (phdr->p_type == PT_PHDR) {
394 DL_INIT_LOADADDR_PROG(app_tpnt->loadaddr, auxvt[AT_PHDR].a_un.a_val - phdr->p_vaddr);
398 if (DL_LOADADDR_BASE(app_tpnt->loadaddr))
399 _dl_debug_early("Position Independent Executable: "
400 "app_tpnt->loadaddr=%x\n", DL_LOADADDR_BASE(app_tpnt->loadaddr));
404 * This is used by gdb to locate the chain of shared libraries that are
407 debug_addr = _dl_zalloc(sizeof(struct r_debug));
409 ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
410 for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
411 if (ppnt->p_type == PT_GNU_RELRO) {
412 relro_addr = ppnt->p_vaddr;
413 relro_size = ppnt->p_memsz;
415 if (!app_mapaddr && (ppnt->p_type == PT_LOAD)) {
416 app_mapaddr = DL_RELOC_ADDR (app_tpnt->loadaddr, ppnt->p_vaddr);
418 if (ppnt->p_type == PT_DYNAMIC) {
419 dpnt = (ElfW(Dyn) *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
420 _dl_parse_dynamic_info(dpnt, app_tpnt->dynamic_info, debug_addr, app_tpnt->loadaddr);
421 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
422 /* Ugly, ugly. We need to call mprotect to change the
423 * protection of the text pages so that we can do the
424 * dynamic linking. We can set the protection back
425 * again once we are done.
427 _dl_debug_early("calling mprotect on the application program\n");
428 /* Now cover the application program. */
429 if (app_tpnt->dynamic_info[DT_TEXTREL]) {
430 ElfW(Phdr) *ppnt_outer = ppnt;
431 ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
432 for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
433 if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
434 _dl_mprotect((void *) (DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr) & PAGE_ALIGN),
435 (DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr) & ADDR_ALIGN) +
436 (unsigned long) ppnt->p_filesz,
437 PROT_READ | PROT_WRITE | PROT_EXEC);
442 if (app_tpnt->dynamic_info[DT_TEXTREL]) {
443 _dl_dprintf(_dl_debug_file, "Can't modify application's text section; use the GCC option -fPIE for position-independent executables.\n");
448 #ifndef ALLOW_ZERO_PLTGOT
449 /* make sure it's really there. */
450 if (app_tpnt->dynamic_info[DT_PLTGOT] == 0)
453 /* OK, we have what we need - slip this one into the list. */
454 app_tpnt = _dl_add_elf_hash_table(_dl_progname, app_tpnt->loadaddr,
455 app_tpnt->dynamic_info,
456 (unsigned long) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr),
458 _dl_loaded_modules->libtype = elf_executable;
459 _dl_loaded_modules->ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
460 _dl_loaded_modules->n_phent = auxvt[AT_PHNUM].a_un.a_val;
461 _dl_symbol_tables = rpnt = _dl_zalloc(sizeof(struct dyn_elf));
462 rpnt->dyn = _dl_loaded_modules;
463 app_tpnt->mapaddr = app_mapaddr;
464 app_tpnt->rtld_flags = unlazy | RTLD_GLOBAL;
465 app_tpnt->usage_count++;
466 app_tpnt->symbol_scope = _dl_symbol_tables;
467 lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT]);
468 #ifdef ALLOW_ZERO_PLTGOT
471 INIT_GOT(lpnt, _dl_loaded_modules);
474 /* OK, fill this in - we did not have this before */
475 if (ppnt->p_type == PT_INTERP) {
476 tpnt->libname = (char *) DL_RELOC_ADDR(app_tpnt->loadaddr, ppnt->p_vaddr);
477 #ifdef __LDSO_SEARCH_INTERP_PATH__
480 /* Store the path where the shared lib loader was found
483 _dl_ldsopath = _dl_strdup(tpnt->libname);
484 ptmp = _dl_strrchr(_dl_ldsopath, '/');
485 if (ptmp != _dl_ldsopath)
488 _dl_debug_early("Lib Loader: (%x) %s\n", (unsigned) DL_LOADADDR_BASE(tpnt->loadaddr), tpnt->libname);
492 /* Discover any TLS sections if the target supports them. */
493 if (ppnt->p_type == PT_TLS) {
494 #if defined(USE_TLS) && USE_TLS
495 if (ppnt->p_memsz > 0) {
496 app_tpnt->l_tls_blocksize = ppnt->p_memsz;
497 app_tpnt->l_tls_align = ppnt->p_align;
498 if (ppnt->p_align == 0)
499 app_tpnt->l_tls_firstbyte_offset = 0;
501 app_tpnt->l_tls_firstbyte_offset =
502 (ppnt->p_vaddr & (ppnt->p_align - 1));
503 app_tpnt->l_tls_initimage_size = ppnt->p_filesz;
504 app_tpnt->l_tls_initimage = (void *) ppnt->p_vaddr;
506 /* This image gets the ID one. */
507 _dl_tls_max_dtv_idx = app_tpnt->l_tls_modid = 1;
510 _dl_debug_early("Found TLS header for appplication program\n");
513 _dl_dprintf(_dl_debug_file, "Program uses unsupported TLS data!\n");
518 app_tpnt->relro_addr = relro_addr;
519 app_tpnt->relro_size = relro_size;
521 #if defined(USE_TLS) && USE_TLS
523 * Adjust the address of the TLS initialization image in
524 * case the executable is actually an ET_DYN object.
526 if (app_tpnt->l_tls_initimage != NULL) {
527 app_tpnt->l_tls_initimage =
528 (char *) app_tpnt->l_tls_initimage + app_tpnt->loadaddr;
529 _dl_debug_early("Relocated TLS initial image from %x to %x (size = %x)\n",
530 (unsigned int)app_tpnt->l_tls_initimage,
531 app_tpnt->l_tls_initimage, app_tpnt->l_tls_initimage_size);
535 #ifdef __SUPPORT_LD_DEBUG__
536 _dl_debug = _dl_getenv("LD_DEBUG", envp);
538 if (_dl_strstr(_dl_debug, "all")) {
539 _dl_debug_detail = _dl_debug_move = _dl_debug_symbols
540 = _dl_debug_reloc = _dl_debug_bindings = _dl_debug_nofixups = (void*)1;
542 _dl_debug_detail = _dl_strstr(_dl_debug, "detail");
543 _dl_debug_move = _dl_strstr(_dl_debug, "move");
544 _dl_debug_symbols = _dl_strstr(_dl_debug, "sym");
545 _dl_debug_reloc = _dl_strstr(_dl_debug, "reloc");
546 _dl_debug_nofixups = _dl_strstr(_dl_debug, "nofix");
547 _dl_debug_bindings = _dl_strstr(_dl_debug, "bind");
552 const char *dl_debug_output;
554 dl_debug_output = _dl_getenv("LD_DEBUG_OUTPUT", envp);
556 if (dl_debug_output) {
557 char tmp[22], *tmp1, *filename;
560 _dl_memset(tmp, 0, sizeof(tmp));
561 tmp1 = _dl_simple_ltoa( tmp, (unsigned long)_dl_getpid());
563 len1 = _dl_strlen(dl_debug_output);
564 len2 = _dl_strlen(tmp1);
566 filename = _dl_malloc(len1 + len2 + 2);
569 _dl_strcpy (filename, dl_debug_output);
570 filename[len1] = '.';
571 _dl_strcpy (&filename[len1+1], tmp1);
573 _dl_debug_file = _dl_open(filename, O_WRONLY|O_CREAT, 0644);
574 if (_dl_debug_file < 0) {
576 _dl_dprintf(_dl_debug_file, "can't open file: '%s'\n",filename);
583 if (_dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL) {
584 trace_loaded_objects++;
587 #ifndef __LDSO_LDD_SUPPORT__
588 if (trace_loaded_objects) {
589 _dl_dprintf(_dl_debug_file, "Use the ldd provided by uClibc\n");
595 * OK, fix one more thing - set up debug_addr so it will point
596 * to our chain. Later we may need to fill in more fields, but this
597 * should be enough for now.
599 debug_addr->r_map = (struct link_map *) _dl_loaded_modules;
600 debug_addr->r_version = 1;
601 debug_addr->r_ldbase = (ElfW(Addr)) DL_LOADADDR_BASE(load_addr);
602 debug_addr->r_brk = (unsigned long) &_dl_debug_state;
603 _dl_debug_addr = debug_addr;
605 /* Do not notify the debugger until the interpreter is in the list */
607 /* OK, we now have the application in the list, and we have some
608 * basic stuff in place. Now search through the list for other shared
609 * libraries that should be loaded, and insert them on the list in the
619 while (*str == ':' || *str == ' ' || *str == '\t')
624 while (*str2 && *str2 != ':' && *str2 != ' ' && *str2 != '\t')
629 if (!_dl_secure || _dl_strchr(str, '/') == NULL) {
630 _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", str, _dl_progname);
632 tpnt1 = _dl_load_shared_library(_dl_secure, &rpnt, NULL, str, trace_loaded_objects);
634 #ifdef __LDSO_LDD_SUPPORT__
635 if (trace_loaded_objects)
636 _dl_dprintf(1, "\t%s => not found\n", str);
640 _dl_dprintf(_dl_debug_file, "%s: can't load " "library '%s'\n", _dl_progname, str);
644 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
646 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
648 #ifdef __LDSO_LDD_SUPPORT__
649 if (trace_loaded_objects &&
650 tpnt1->usage_count == 1) {
651 /* This is a real hack to make
652 * ldd not print the library
653 * itself when run on a
656 if (_dl_strcmp(_dl_progname, str) != 0)
657 _dl_dprintf(1, "\t%s => %s (%x)\n", str, tpnt1->libname,
658 DL_LOADADDR_BASE(tpnt1->loadaddr));
666 while (*str == ':' || *str == ' ' || *str == '\t')
671 #ifdef __LDSO_PRELOAD_FILE_SUPPORT__
678 if (_dl_stat(LDSO_PRELOAD, &st) || st.st_size == 0) {
682 if ((fd = _dl_open(LDSO_PRELOAD, O_RDONLY, 0)) < 0) {
683 _dl_dprintf(_dl_debug_file, "%s: can't open file '%s'\n",
684 _dl_progname, LDSO_PRELOAD);
688 preload = (caddr_t) _dl_mmap(0, st.st_size + 1,
689 PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
691 if (preload == (caddr_t) -1) {
692 _dl_dprintf(_dl_debug_file, "%s:%i: can't map '%s'\n",
693 _dl_progname, __LINE__, LDSO_PRELOAD);
697 /* convert all separators and comments to spaces */
698 for (cp = preload; *cp; /*nada */ ) {
699 if (*cp == ':' || *cp == '\t' || *cp == '\n') {
701 } else if (*cp == '#') {
704 } while (*cp != '\n' && *cp != '\0');
710 /* find start of first library */
711 for (cp = preload; *cp && *cp == ' '; cp++)
715 /* find end of library */
716 for (cp2 = cp; *cp && *cp != ' '; cp++)
721 _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", cp2, _dl_progname);
723 tpnt1 = _dl_load_shared_library(0, &rpnt, NULL, cp2, trace_loaded_objects);
725 #ifdef __LDSO_LDD_SUPPORT__
726 if (trace_loaded_objects)
727 _dl_dprintf(1, "\t%s => not found\n", cp2);
731 _dl_dprintf(_dl_debug_file, "%s: can't load library '%s'\n", _dl_progname, cp2);
735 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
737 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
739 #ifdef __LDSO_LDD_SUPPORT__
740 if (trace_loaded_objects &&
741 tpnt1->usage_count == 1) {
742 _dl_dprintf(1, "\t%s => %s (%x)\n",
744 DL_LOADADDR_BASE(tpnt1->loadaddr));
749 /* find start of next library */
751 for ( /*nada */ ; *cp && *cp == ' '; cp++)
755 _dl_munmap(preload, st.st_size + 1);
757 #endif /* __LDSO_PRELOAD_FILE_SUPPORT__ */
760 for (tcurr = _dl_loaded_modules; tcurr; tcurr = tcurr->next) {
761 ElfW(Dyn) *this_dpnt;
764 for (this_dpnt = (ElfW(Dyn) *) tcurr->dynamic_addr; this_dpnt->d_tag; this_dpnt++) {
765 if (this_dpnt->d_tag == DT_NEEDED) {
767 struct init_fini_list *tmp;
769 lpntstr = (char*) (tcurr->dynamic_info[DT_STRTAB] + this_dpnt->d_un.d_val);
770 name = _dl_get_last_path_component(lpntstr);
771 if (_dl_strcmp(name, UCLIBC_LDSO) == 0)
774 _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", lpntstr, _dl_progname);
776 if (!(tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, trace_loaded_objects))) {
777 #ifdef __LDSO_LDD_SUPPORT__
778 if (trace_loaded_objects) {
779 _dl_dprintf(1, "\t%s => not found\n", lpntstr);
784 _dl_dprintf(_dl_debug_file, "%s: can't load library '%s'\n", _dl_progname, lpntstr);
789 tmp = alloca(sizeof(struct init_fini_list)); /* Allocates on stack, no need to free this memory */
791 tmp->next = tcurr->init_fini;
792 tcurr->init_fini = tmp;
794 tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
796 _dl_debug_early("Loading: (%x) %s\n", DL_LOADADDR_BASE(tpnt1->loadaddr), tpnt1->libname);
798 #ifdef __LDSO_LDD_SUPPORT__
799 if (trace_loaded_objects &&
800 tpnt1->usage_count == 1) {
801 _dl_dprintf(1, "\t%s => %s (%x)\n",
802 lpntstr, tpnt1->libname,
803 DL_LOADADDR_BASE(tpnt1->loadaddr));
811 --nlist; /* Exclude the application. */
812 init_fini_list = _dl_malloc(nlist * sizeof(struct elf_resolve *));
814 for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
815 init_fini_list[i++] = tcurr;
818 /* Sort the INIT/FINI list in dependency order. */
819 for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
822 for (j = 0; init_fini_list[j] != tcurr; ++j)
824 for (k = j + 1; k < nlist; ++k) {
825 struct init_fini_list *runp = init_fini_list[k]->init_fini;
827 for (; runp; runp = runp->next) {
828 if (runp->tpnt == tcurr) {
829 struct elf_resolve *here = init_fini_list[k];
830 _dl_if_debug_dprint("Move %s from pos %d to %d in INIT/FINI list\n", here->libname, k, j);
831 for (i = (k - j); i; --i)
832 init_fini_list[i+j] = init_fini_list[i+j-1];
833 init_fini_list[j] = here;
840 #ifdef __SUPPORT_LD_DEBUG__
842 _dl_dprintf(_dl_debug_file, "\nINIT/FINI order and dependencies:\n");
843 for (i = 0; i < nlist; i++) {
844 struct init_fini_list *tmp;
846 _dl_dprintf(_dl_debug_file, "lib: %s has deps:\n",
847 init_fini_list[i]->libname);
848 tmp = init_fini_list[i]->init_fini;
849 for (; tmp; tmp = tmp->next)
850 _dl_dprintf(_dl_debug_file, " %s ", tmp->tpnt->libname);
851 _dl_dprintf(_dl_debug_file, "\n");
857 * If the program interpreter is not in the module chain, add it.
858 * This will be required for dlopen to be able to access the internal
859 * functions in the dynamic linker and to relocate the interpreter
860 * again once all libs are loaded.
863 ElfW(Ehdr) *epnt = (ElfW(Ehdr) *) auxvt[AT_BASE].a_un.a_val;
864 ElfW(Phdr) *myppnt = (ElfW(Phdr) *) DL_RELOC_ADDR(load_addr, epnt->e_phoff);
867 tpnt = _dl_add_elf_hash_table(tpnt->libname, load_addr,
869 (unsigned long)tpnt->dynamic_addr,
872 if (_dl_stat(tpnt->libname, &st) >= 0) {
873 tpnt->st_dev = st.st_dev;
874 tpnt->st_ino = st.st_ino;
876 tpnt->n_phent = epnt->e_phnum;
878 for (j = 0; j < epnt->e_phnum; j++, myppnt++) {
879 if (myppnt->p_type == PT_GNU_RELRO) {
880 tpnt->relro_addr = myppnt->p_vaddr;
881 tpnt->relro_size = myppnt->p_memsz;
885 tpnt->libtype = program_interpreter;
887 tpnt->symbol_scope = _dl_symbol_tables;
889 rpnt->next = _dl_zalloc(sizeof(struct dyn_elf));
890 rpnt->next->prev = rpnt;
893 rpnt = _dl_zalloc(sizeof(struct dyn_elf));
896 tpnt->rtld_flags = RTLD_NOW | RTLD_GLOBAL; /* Must not be LAZY */
897 #ifdef RERELOCATE_LDSO
898 /* Only rerelocate functions for now. */
899 tpnt->init_flag = RELOCS_DONE;
900 lpnt = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT]);
901 # ifdef ALLOW_ZERO_PLTGOT
902 if (tpnt->dynamic_info[DT_PLTGOT])
904 INIT_GOT(lpnt, tpnt);
906 tpnt->init_flag = RELOCS_DONE | JMP_RELOCS_DONE;
911 #ifdef __LDSO_LDD_SUPPORT__
912 /* End of the line for ldd.... */
913 if (trace_loaded_objects) {
914 _dl_dprintf(1, "\t%s => %s (%x)\n",
915 rpnt->dyn->libname + _dl_strlen(_dl_ldsopath) + 1,
916 rpnt->dyn->libname, DL_LOADADDR_BASE(rpnt->dyn->loadaddr));
921 #if defined(USE_TLS) && USE_TLS
922 /* We do not initialize any of the TLS functionality unless any of the
923 * initial modules uses TLS. This makes dynamic loading of modules with
924 * TLS impossible, but to support it requires either eagerly doing setup
925 * now or lazily doing it later. Doing it now makes us incompatible with
926 * an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
927 * used. Trying to do it lazily is too hairy to try when there could be
928 * multiple threads (from a non-TLS-using libpthread). */
929 bool was_tls_init_tp_called = tls_init_tp_called;
931 _dl_debug_early("Calling init_tls()!\n");
935 #ifdef __UCLIBC_HAS_SSP__
936 /* Set up the stack checker's canary. */
937 stack_chk_guard = _dl_setup_stack_chk_guard ();
938 # ifdef THREAD_SET_STACK_GUARD
939 THREAD_SET_STACK_GUARD (stack_chk_guard);
940 # ifdef __UCLIBC_HAS_SSP_COMPAT__
941 __guard = stack_chk_guard;
944 __stack_chk_guard = stack_chk_guard;
949 _dl_debug_early("Beginning relocation fixups\n");
953 * Relocation of the GOT entries for MIPS have to be done
954 * after all the libraries have been loaded.
956 _dl_perform_mips_global_got_relocations(_dl_loaded_modules, !unlazy);
960 * OK, now all of the kids are tucked into bed in their proper
961 * addresses. Now we go through and look for REL and RELA records that
962 * indicate fixups to the GOT tables. We need to do this in reverse
963 * order so that COPY directives work correctly.
965 if (_dl_symbol_tables)
966 if (_dl_fixup(_dl_symbol_tables, unlazy))
969 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
970 if (tpnt->relro_size)
971 _dl_protect_relro (tpnt);
974 #if defined(USE_TLS) && USE_TLS
975 if (!was_tls_init_tp_called && _dl_tls_max_dtv_idx > 0)
976 ++_dl_tls_generation;
978 _dl_debug_early("Calling _dl_allocate_tls_init()!\n");
980 /* Now that we have completed relocation, the initializer data
981 for the TLS blocks has its final values and we can copy them
982 into the main thread's TLS area, which we allocated above. */
983 _dl_allocate_tls_init (tcbp);
985 /* And finally install it for the main thread. If ld.so itself uses
986 TLS we know the thread pointer was initialized earlier. */
987 if (! tls_init_tp_called) {
988 const char *lossage = (char *) TLS_INIT_TP (tcbp, USE___THREAD);
989 if (__builtin_expect (lossage != NULL, 0)) {
990 _dl_debug_early("cannot set up thread-local storage: %s\n", lossage);
996 /* OK, at this point things are pretty much ready to run. Now we need
997 * to touch up a few items that are required, and then we can let the
998 * user application have at it. Note that the dynamic linker itself
999 * is not guaranteed to be fully dynamicly linked if we are using
1000 * ld.so.1, so we have to look up each symbol individually.
1003 _dl_envp = (unsigned long *) (intptr_t) _dl_find_hash(__C_SYMBOL_PREFIX__ "__environ", _dl_symbol_tables, NULL, 0, NULL);
1005 *_dl_envp = (unsigned long) envp;
1007 #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
1012 /* We had to set the protections of all pages to R/W for
1013 * dynamic linking. Set text pages back to R/O.
1015 for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
1016 for (myppnt = tpnt->ppnt, j = 0; j < tpnt->n_phent; j++, myppnt++) {
1017 if (myppnt->p_type == PT_LOAD && !(myppnt->p_flags & PF_W) && tpnt->dynamic_info[DT_TEXTREL]) {
1018 _dl_mprotect((void *) (DL_RELOC_ADDR(tpnt->loadaddr, myppnt->p_vaddr) & PAGE_ALIGN),
1019 (myppnt->p_vaddr & ADDR_ALIGN) + (unsigned long) myppnt->p_filesz, LXFLAGS(myppnt->p_flags));
1026 /* Notify the debugger we have added some objects. */
1027 _dl_debug_addr->r_state = RT_ADD;
1030 /* Run pre-initialization functions for the executable. */
1031 _dl_run_array_forward(_dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAY],
1032 _dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAYSZ],
1033 _dl_loaded_modules->loadaddr);
1035 /* Run initialization functions for loaded objects. For the
1036 main executable, they will be run from __uClibc_main. */
1037 for (i = nlist; i; --i) {
1038 tpnt = init_fini_list[i-1];
1039 tpnt->init_fini = NULL; /* Clear, since alloca was used */
1040 if (tpnt->init_flag & INIT_FUNCS_CALLED)
1042 tpnt->init_flag |= INIT_FUNCS_CALLED;
1044 if (tpnt->dynamic_info[DT_INIT]) {
1045 void (*dl_elf_func) (void);
1047 dl_elf_func = (void (*)(void)) DL_RELOC_ADDR(tpnt->loadaddr, tpnt->dynamic_info[DT_INIT]);
1049 _dl_if_debug_dprint("calling INIT: %s\n\n", tpnt->libname);
1051 DL_CALL_FUNC_AT_ADDR (dl_elf_func, tpnt->loadaddr, (void(*)(void)));
1054 _dl_run_init_array(tpnt);
1057 /* Find the real malloc function and make ldso functions use that from now on */
1058 _dl_malloc_function = (void* (*)(size_t)) (intptr_t) _dl_find_hash(__C_SYMBOL_PREFIX__ "malloc",
1059 _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT, NULL);
1061 #if defined(USE_TLS) && USE_TLS
1062 /* Find the real functions and make ldso functions use them from now on */
1063 _dl_calloc_function = (void* (*)(size_t, size_t)) (intptr_t)
1064 _dl_find_hash(__C_SYMBOL_PREFIX__ "calloc", _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT, NULL);
1066 _dl_realloc_function = (void* (*)(void *, size_t)) (intptr_t)
1067 _dl_find_hash(__C_SYMBOL_PREFIX__ "realloc", _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT, NULL);
1069 _dl_free_function = (void (*)(void *)) (intptr_t)
1070 _dl_find_hash(__C_SYMBOL_PREFIX__ "free", _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT, NULL);
1072 _dl_memalign_function = (void* (*)(size_t, size_t)) (intptr_t)
1073 _dl_find_hash(__C_SYMBOL_PREFIX__ "memalign", _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT, NULL);
1077 /* Notify the debugger that all objects are now mapped in. */
1078 _dl_debug_addr->r_state = RT_CONSISTENT;
1082 #include "dl-hash.c"