]> sourceware.org Git - glibc.git/blob - elf/rtld.c
elf: Implement __libc_early_init
[glibc.git] / elf / rtld.c
1 /* Run time dynamic linker.
2 Copyright (C) 1995-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <errno.h>
20 #include <dlfcn.h>
21 #include <fcntl.h>
22 #include <stdbool.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <sys/mman.h>
27 #include <sys/param.h>
28 #include <sys/stat.h>
29 #include <ldsodefs.h>
30 #include <_itoa.h>
31 #include <entry.h>
32 #include <fpu_control.h>
33 #include <hp-timing.h>
34 #include <libc-lock.h>
35 #include "dynamic-link.h"
36 #include <dl-librecon.h>
37 #include <unsecvars.h>
38 #include <dl-cache.h>
39 #include <dl-osinfo.h>
40 #include <dl-procinfo.h>
41 #include <dl-prop.h>
42 #include <dl-vdso.h>
43 #include <dl-vdso-setup.h>
44 #include <tls.h>
45 #include <stap-probe.h>
46 #include <stackinfo.h>
47 #include <not-cancel.h>
48 #include <array_length.h>
49 #include <libc-early-init.h>
50
51 #include <assert.h>
52
53 /* Only enables rtld profiling for architectures which provides non generic
54 hp-timing support. The generic support requires either syscall
55 (clock_gettime), which will incur in extra overhead on loading time.
56 Using vDSO is also an option, but it will require extra support on loader
57 to setup the vDSO pointer before its usage. */
58 #if HP_TIMING_INLINE
59 # define RLTD_TIMING_DECLARE(var, classifier,...) \
60 classifier hp_timing_t var __VA_ARGS__
61 # define RTLD_TIMING_VAR(var) RLTD_TIMING_DECLARE (var, )
62 # define RTLD_TIMING_SET(var, value) (var) = (value)
63 # define RTLD_TIMING_REF(var) &(var)
64
65 static inline void
66 rtld_timer_start (hp_timing_t *var)
67 {
68 HP_TIMING_NOW (*var);
69 }
70
71 static inline void
72 rtld_timer_stop (hp_timing_t *var, hp_timing_t start)
73 {
74 hp_timing_t stop;
75 HP_TIMING_NOW (stop);
76 HP_TIMING_DIFF (*var, start, stop);
77 }
78
79 static inline void
80 rtld_timer_accum (hp_timing_t *sum, hp_timing_t start)
81 {
82 hp_timing_t stop;
83 rtld_timer_stop (&stop, start);
84 HP_TIMING_ACCUM_NT(*sum, stop);
85 }
86 #else
87 # define RLTD_TIMING_DECLARE(var, classifier...)
88 # define RTLD_TIMING_SET(var, value)
89 # define RTLD_TIMING_VAR(var)
90 # define RTLD_TIMING_REF(var) 0
91 # define rtld_timer_start(var)
92 # define rtld_timer_stop(var, start)
93 # define rtld_timer_accum(sum, start)
94 #endif
95
96 /* Avoid PLT use for our local calls at startup. */
97 extern __typeof (__mempcpy) __mempcpy attribute_hidden;
98
99 /* GCC has mental blocks about _exit. */
100 extern __typeof (_exit) exit_internal asm ("_exit") attribute_hidden;
101 #define _exit exit_internal
102
103 /* Helper function to handle errors while resolving symbols. */
104 static void print_unresolved (int errcode, const char *objname,
105 const char *errsting);
106
107 /* Helper function to handle errors when a version is missing. */
108 static void print_missing_version (int errcode, const char *objname,
109 const char *errsting);
110
111 /* Print the various times we collected. */
112 static void print_statistics (const hp_timing_t *total_timep);
113
114 /* Length limits for names and paths, to protect the dynamic linker,
115 particularly when __libc_enable_secure is active. */
116 #ifdef NAME_MAX
117 # define SECURE_NAME_LIMIT NAME_MAX
118 #else
119 # define SECURE_NAME_LIMIT 255
120 #endif
121 #ifdef PATH_MAX
122 # define SECURE_PATH_LIMIT PATH_MAX
123 #else
124 # define SECURE_PATH_LIMIT 1024
125 #endif
126
127 /* Strings containing colon-separated lists of audit modules. */
128 struct audit_list
129 {
130 /* Array of strings containing colon-separated path lists. Each
131 audit module needs its own namespace, so pre-allocate the largest
132 possible list. */
133 const char *audit_strings[DL_NNS];
134
135 /* Number of entries added to audit_strings. */
136 size_t length;
137
138 /* Index into the audit_strings array (for the iteration phase). */
139 size_t current_index;
140
141 /* Tail of audit_strings[current_index] which still needs
142 processing. */
143 const char *current_tail;
144
145 /* Scratch buffer for returning a name which is part of the strings
146 in audit_strings. */
147 char fname[SECURE_NAME_LIMIT];
148 };
149
150 /* Creates an empty audit list. */
151 static void audit_list_init (struct audit_list *);
152
153 /* Add a string to the end of the audit list, for later parsing. Must
154 not be called after audit_list_next. */
155 static void audit_list_add_string (struct audit_list *, const char *);
156
157 /* Add the audit strings from the link map, found in the dynamic
158 segment at TG (either DT_AUDIT and DT_DEPAUDIT). Must be called
159 before audit_list_next. */
160 static void audit_list_add_dynamic_tag (struct audit_list *,
161 struct link_map *,
162 unsigned int tag);
163
164 /* Extract the next audit module from the audit list. Only modules
165 for which dso_name_valid_for_suid is true are returned. Must be
166 called after all the audit_list_add_string,
167 audit_list_add_dynamic_tags calls. */
168 static const char *audit_list_next (struct audit_list *);
169
170 /* This is a list of all the modes the dynamic loader can be in. */
171 enum mode { normal, list, verify, trace };
172
173 /* Process all environments variables the dynamic linker must recognize.
174 Since all of them start with `LD_' we are a bit smarter while finding
175 all the entries. */
176 static void process_envvars (enum mode *modep, struct audit_list *);
177
178 #ifdef DL_ARGV_NOT_RELRO
179 int _dl_argc attribute_hidden;
180 char **_dl_argv = NULL;
181 /* Nonzero if we were run directly. */
182 unsigned int _dl_skip_args attribute_hidden;
183 #else
184 int _dl_argc attribute_relro attribute_hidden;
185 char **_dl_argv attribute_relro = NULL;
186 unsigned int _dl_skip_args attribute_relro attribute_hidden;
187 #endif
188 rtld_hidden_data_def (_dl_argv)
189
190 #ifndef THREAD_SET_STACK_GUARD
191 /* Only exported for architectures that don't store the stack guard canary
192 in thread local area. */
193 uintptr_t __stack_chk_guard attribute_relro;
194 #endif
195
196 /* Only exported for architectures that don't store the pointer guard
197 value in thread local area. */
198 uintptr_t __pointer_chk_guard_local
199 attribute_relro attribute_hidden __attribute__ ((nocommon));
200 #ifndef THREAD_SET_POINTER_GUARD
201 strong_alias (__pointer_chk_guard_local, __pointer_chk_guard)
202 #endif
203
204 /* Check that AT_SECURE=0, or that the passed name does not contain
205 directories and is not overly long. Reject empty names
206 unconditionally. */
207 static bool
208 dso_name_valid_for_suid (const char *p)
209 {
210 if (__glibc_unlikely (__libc_enable_secure))
211 {
212 /* Ignore pathnames with directories for AT_SECURE=1
213 programs, and also skip overlong names. */
214 size_t len = strlen (p);
215 if (len >= SECURE_NAME_LIMIT || memchr (p, '/', len) != NULL)
216 return false;
217 }
218 return *p != '\0';
219 }
220
221 static void
222 audit_list_init (struct audit_list *list)
223 {
224 list->length = 0;
225 list->current_index = 0;
226 list->current_tail = NULL;
227 }
228
229 static void
230 audit_list_add_string (struct audit_list *list, const char *string)
231 {
232 /* Empty strings do not load anything. */
233 if (*string == '\0')
234 return;
235
236 if (list->length == array_length (list->audit_strings))
237 _dl_fatal_printf ("Fatal glibc error: Too many audit modules requested\n");
238
239 list->audit_strings[list->length++] = string;
240
241 /* Initialize processing of the first string for
242 audit_list_next. */
243 if (list->length == 1)
244 list->current_tail = string;
245 }
246
247 static void
248 audit_list_add_dynamic_tag (struct audit_list *list, struct link_map *main_map,
249 unsigned int tag)
250 {
251 ElfW(Dyn) *info = main_map->l_info[ADDRIDX (tag)];
252 const char *strtab = (const char *) D_PTR (main_map, l_info[DT_STRTAB]);
253 if (info != NULL)
254 audit_list_add_string (list, strtab + info->d_un.d_val);
255 }
256
257 static const char *
258 audit_list_next (struct audit_list *list)
259 {
260 if (list->current_tail == NULL)
261 return NULL;
262
263 while (true)
264 {
265 /* Advance to the next string in audit_strings if the current
266 string has been exhausted. */
267 while (*list->current_tail == '\0')
268 {
269 ++list->current_index;
270 if (list->current_index == list->length)
271 {
272 list->current_tail = NULL;
273 return NULL;
274 }
275 list->current_tail = list->audit_strings[list->current_index];
276 }
277
278 /* Split the in-string audit list at the next colon colon. */
279 size_t len = strcspn (list->current_tail, ":");
280 if (len > 0 && len < sizeof (list->fname))
281 {
282 memcpy (list->fname, list->current_tail, len);
283 list->fname[len] = '\0';
284 }
285 else
286 /* Mark the name as unusable for dso_name_valid_for_suid. */
287 list->fname[0] = '\0';
288
289 /* Skip over the substring and the following delimiter. */
290 list->current_tail += len;
291 if (*list->current_tail == ':')
292 ++list->current_tail;
293
294 /* If the name is valid, return it. */
295 if (dso_name_valid_for_suid (list->fname))
296 return list->fname;
297
298 /* Otherwise wrap around to find the next list element. . */
299 }
300 }
301
302 #ifndef HAVE_INLINED_SYSCALLS
303 /* Set nonzero during loading and initialization of executable and
304 libraries, cleared before the executable's entry point runs. This
305 must not be initialized to nonzero, because the unused dynamic
306 linker loaded in for libc.so's "ld.so.1" dep will provide the
307 definition seen by libc.so's initializer; that value must be zero,
308 and will be since that dynamic linker's _dl_start and dl_main will
309 never be called. */
310 int _dl_starting_up = 0;
311 rtld_hidden_def (_dl_starting_up)
312 #endif
313
314 /* This is the structure which defines all variables global to ld.so
315 (except those which cannot be added for some reason). */
316 struct rtld_global _rtld_global =
317 {
318 /* Generally the default presumption without further information is an
319 * executable stack but this is not true for all platforms. */
320 ._dl_stack_flags = DEFAULT_STACK_PERMS,
321 #ifdef _LIBC_REENTRANT
322 ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
323 ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
324 #endif
325 ._dl_nns = 1,
326 ._dl_ns =
327 {
328 #ifdef _LIBC_REENTRANT
329 [LM_ID_BASE] = { ._ns_unique_sym_table
330 = { .lock = _RTLD_LOCK_RECURSIVE_INITIALIZER } }
331 #endif
332 }
333 };
334 /* If we would use strong_alias here the compiler would see a
335 non-hidden definition. This would undo the effect of the previous
336 declaration. So spell out was strong_alias does plus add the
337 visibility attribute. */
338 extern struct rtld_global _rtld_local
339 __attribute__ ((alias ("_rtld_global"), visibility ("hidden")));
340
341
342 /* This variable is similar to _rtld_local, but all values are
343 read-only after relocation. */
344 struct rtld_global_ro _rtld_global_ro attribute_relro =
345 {
346 /* Get architecture specific initializer. */
347 #include <dl-procinfo.c>
348 #ifdef NEED_DL_SYSINFO
349 ._dl_sysinfo = DL_SYSINFO_DEFAULT,
350 #endif
351 ._dl_debug_fd = STDERR_FILENO,
352 ._dl_use_load_bias = -2,
353 ._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID,
354 #if !HAVE_TUNABLES
355 ._dl_hwcap_mask = HWCAP_IMPORTANT,
356 #endif
357 ._dl_lazy = 1,
358 ._dl_fpu_control = _FPU_DEFAULT,
359 ._dl_pagesize = EXEC_PAGESIZE,
360 ._dl_inhibit_cache = 0,
361
362 /* Function pointers. */
363 ._dl_debug_printf = _dl_debug_printf,
364 ._dl_mcount = _dl_mcount,
365 ._dl_lookup_symbol_x = _dl_lookup_symbol_x,
366 ._dl_open = _dl_open,
367 ._dl_close = _dl_close,
368 ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
369 #ifdef HAVE_DL_DISCOVER_OSVERSION
370 ._dl_discover_osversion = _dl_discover_osversion
371 #endif
372 };
373 /* If we would use strong_alias here the compiler would see a
374 non-hidden definition. This would undo the effect of the previous
375 declaration. So spell out was strong_alias does plus add the
376 visibility attribute. */
377 extern struct rtld_global_ro _rtld_local_ro
378 __attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
379
380
381 static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
382 ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv);
383
384 /* These two variables cannot be moved into .data.rel.ro. */
385 static struct libname_list _dl_rtld_libname;
386 static struct libname_list _dl_rtld_libname2;
387
388 /* Variable for statistics. */
389 RLTD_TIMING_DECLARE (relocate_time, static);
390 RLTD_TIMING_DECLARE (load_time, static, attribute_relro);
391 RLTD_TIMING_DECLARE (start_time, static, attribute_relro);
392
393 /* Additional definitions needed by TLS initialization. */
394 #ifdef TLS_INIT_HELPER
395 TLS_INIT_HELPER
396 #endif
397
398 /* Helper function for syscall implementation. */
399 #ifdef DL_SYSINFO_IMPLEMENTATION
400 DL_SYSINFO_IMPLEMENTATION
401 #endif
402
403 /* Before ld.so is relocated we must not access variables which need
404 relocations. This means variables which are exported. Variables
405 declared as static are fine. If we can mark a variable hidden this
406 is fine, too. The latter is important here. We can avoid setting
407 up a temporary link map for ld.so if we can mark _rtld_global as
408 hidden. */
409 #ifdef PI_STATIC_AND_HIDDEN
410 # define DONT_USE_BOOTSTRAP_MAP 1
411 #endif
412
413 #ifdef DONT_USE_BOOTSTRAP_MAP
414 static ElfW(Addr) _dl_start_final (void *arg);
415 #else
416 struct dl_start_final_info
417 {
418 struct link_map l;
419 RTLD_TIMING_VAR (start_time);
420 };
421 static ElfW(Addr) _dl_start_final (void *arg,
422 struct dl_start_final_info *info);
423 #endif
424
425 /* These defined magically in the linker script. */
426 extern char _begin[] attribute_hidden;
427 extern char _etext[] attribute_hidden;
428 extern char _end[] attribute_hidden;
429
430
431 #ifdef RTLD_START
432 RTLD_START
433 #else
434 # error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
435 #endif
436
437 /* This is the second half of _dl_start (below). It can be inlined safely
438 under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
439 references. When the tools don't permit us to avoid using a GOT entry
440 for _dl_rtld_global (no attribute_hidden support), we must make sure
441 this function is not inlined (see below). */
442
443 #ifdef DONT_USE_BOOTSTRAP_MAP
444 static inline ElfW(Addr) __attribute__ ((always_inline))
445 _dl_start_final (void *arg)
446 #else
447 static ElfW(Addr) __attribute__ ((noinline))
448 _dl_start_final (void *arg, struct dl_start_final_info *info)
449 #endif
450 {
451 ElfW(Addr) start_addr;
452
453 /* If it hasn't happen yet record the startup time. */
454 rtld_timer_start (&start_time);
455 #if !defined DONT_USE_BOOTSTRAP_MAP
456 RTLD_TIMING_SET (start_time, info->start_time);
457 #endif
458
459 /* Transfer data about ourselves to the permanent link_map structure. */
460 #ifndef DONT_USE_BOOTSTRAP_MAP
461 GL(dl_rtld_map).l_addr = info->l.l_addr;
462 GL(dl_rtld_map).l_ld = info->l.l_ld;
463 memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
464 sizeof GL(dl_rtld_map).l_info);
465 GL(dl_rtld_map).l_mach = info->l.l_mach;
466 GL(dl_rtld_map).l_relocated = 1;
467 #endif
468 _dl_setup_hash (&GL(dl_rtld_map));
469 GL(dl_rtld_map).l_real = &GL(dl_rtld_map);
470 GL(dl_rtld_map).l_map_start = (ElfW(Addr)) _begin;
471 GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end;
472 GL(dl_rtld_map).l_text_end = (ElfW(Addr)) _etext;
473 /* Copy the TLS related data if necessary. */
474 #ifndef DONT_USE_BOOTSTRAP_MAP
475 # if NO_TLS_OFFSET != 0
476 GL(dl_rtld_map).l_tls_offset = NO_TLS_OFFSET;
477 # endif
478 #endif
479
480 /* Initialize the stack end variable. */
481 __libc_stack_end = __builtin_frame_address (0);
482
483 /* Call the OS-dependent function to set up life so we can do things like
484 file access. It will call `dl_main' (below) to do all the real work
485 of the dynamic linker, and then unwind our frame and run the user
486 entry point on the same stack we entered on. */
487 start_addr = _dl_sysdep_start (arg, &dl_main);
488
489 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS))
490 {
491 RTLD_TIMING_VAR (rtld_total_time);
492 rtld_timer_stop (&rtld_total_time, start_time);
493 print_statistics (RTLD_TIMING_REF(rtld_total_time));
494 }
495
496 return start_addr;
497 }
498
499 static ElfW(Addr) __attribute_used__
500 _dl_start (void *arg)
501 {
502 #ifdef DONT_USE_BOOTSTRAP_MAP
503 # define bootstrap_map GL(dl_rtld_map)
504 #else
505 struct dl_start_final_info info;
506 # define bootstrap_map info.l
507 #endif
508
509 /* This #define produces dynamic linking inline functions for
510 bootstrap relocation instead of general-purpose relocation.
511 Since ld.so must not have any undefined symbols the result
512 is trivial: always the map of ld.so itself. */
513 #define RTLD_BOOTSTRAP
514 #define BOOTSTRAP_MAP (&bootstrap_map)
515 #define RESOLVE_MAP(sym, version, flags) BOOTSTRAP_MAP
516 #include "dynamic-link.h"
517
518 #ifdef DONT_USE_BOOTSTRAP_MAP
519 rtld_timer_start (&start_time);
520 #else
521 rtld_timer_start (&info.start_time);
522 #endif
523
524 /* Partly clean the `bootstrap_map' structure up. Don't use
525 `memset' since it might not be built in or inlined and we cannot
526 make function calls at this point. Use '__builtin_memset' if we
527 know it is available. We do not have to clear the memory if we
528 do not have to use the temporary bootstrap_map. Global variables
529 are initialized to zero by default. */
530 #ifndef DONT_USE_BOOTSTRAP_MAP
531 # ifdef HAVE_BUILTIN_MEMSET
532 __builtin_memset (bootstrap_map.l_info, '\0', sizeof (bootstrap_map.l_info));
533 # else
534 for (size_t cnt = 0;
535 cnt < sizeof (bootstrap_map.l_info) / sizeof (bootstrap_map.l_info[0]);
536 ++cnt)
537 bootstrap_map.l_info[cnt] = 0;
538 # endif
539 #endif
540
541 /* Figure out the run-time load address of the dynamic linker itself. */
542 bootstrap_map.l_addr = elf_machine_load_address ();
543
544 /* Read our own dynamic section and fill in the info array. */
545 bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
546 elf_get_dynamic_info (&bootstrap_map, NULL);
547
548 #if NO_TLS_OFFSET != 0
549 bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
550 #endif
551
552 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
553 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info);
554 #endif
555
556 if (bootstrap_map.l_addr || ! bootstrap_map.l_info[VALIDX(DT_GNU_PRELINKED)])
557 {
558 /* Relocate ourselves so we can do normal function calls and
559 data access using the global offset table. */
560
561 ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, 0, 0);
562 }
563 bootstrap_map.l_relocated = 1;
564
565 /* Please note that we don't allow profiling of this object and
566 therefore need not test whether we have to allocate the array
567 for the relocation results (as done in dl-reloc.c). */
568
569 /* Now life is sane; we can call functions and access global data.
570 Set up to use the operating system facilities, and find out from
571 the operating system's program loader where to find the program
572 header table in core. Put the rest of _dl_start into a separate
573 function, that way the compiler cannot put accesses to the GOT
574 before ELF_DYNAMIC_RELOCATE. */
575
576 __rtld_malloc_init_stubs ();
577
578 {
579 #ifdef DONT_USE_BOOTSTRAP_MAP
580 ElfW(Addr) entry = _dl_start_final (arg);
581 #else
582 ElfW(Addr) entry = _dl_start_final (arg, &info);
583 #endif
584
585 #ifndef ELF_MACHINE_START_ADDRESS
586 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
587 #endif
588
589 return ELF_MACHINE_START_ADDRESS (GL(dl_ns)[LM_ID_BASE]._ns_loaded, entry);
590 }
591 }
592
593
594
595 /* Now life is peachy; we can do all normal operations.
596 On to the real work. */
597
598 /* Some helper functions. */
599
600 /* Arguments to relocate_doit. */
601 struct relocate_args
602 {
603 struct link_map *l;
604 int reloc_mode;
605 };
606
607 struct map_args
608 {
609 /* Argument to map_doit. */
610 const char *str;
611 struct link_map *loader;
612 int mode;
613 /* Return value of map_doit. */
614 struct link_map *map;
615 };
616
617 struct dlmopen_args
618 {
619 const char *fname;
620 struct link_map *map;
621 };
622
623 struct lookup_args
624 {
625 const char *name;
626 struct link_map *map;
627 void *result;
628 };
629
630 /* Arguments to version_check_doit. */
631 struct version_check_args
632 {
633 int doexit;
634 int dotrace;
635 };
636
637 static void
638 relocate_doit (void *a)
639 {
640 struct relocate_args *args = (struct relocate_args *) a;
641
642 _dl_relocate_object (args->l, args->l->l_scope, args->reloc_mode, 0);
643 }
644
645 static void
646 map_doit (void *a)
647 {
648 struct map_args *args = (struct map_args *) a;
649 int type = (args->mode == __RTLD_OPENEXEC) ? lt_executable : lt_library;
650 args->map = _dl_map_object (args->loader, args->str, type, 0,
651 args->mode, LM_ID_BASE);
652 }
653
654 static void
655 dlmopen_doit (void *a)
656 {
657 struct dlmopen_args *args = (struct dlmopen_args *) a;
658 args->map = _dl_open (args->fname,
659 (RTLD_LAZY | __RTLD_DLOPEN | __RTLD_AUDIT
660 | __RTLD_SECURE),
661 dl_main, LM_ID_NEWLM, _dl_argc, _dl_argv,
662 __environ);
663 }
664
665 static void
666 lookup_doit (void *a)
667 {
668 struct lookup_args *args = (struct lookup_args *) a;
669 const ElfW(Sym) *ref = NULL;
670 args->result = NULL;
671 lookup_t l = _dl_lookup_symbol_x (args->name, args->map, &ref,
672 args->map->l_local_scope, NULL, 0,
673 DL_LOOKUP_RETURN_NEWEST, NULL);
674 if (ref != NULL)
675 args->result = DL_SYMBOL_ADDRESS (l, ref);
676 }
677
678 static void
679 version_check_doit (void *a)
680 {
681 struct version_check_args *args = (struct version_check_args *) a;
682 if (_dl_check_all_versions (GL(dl_ns)[LM_ID_BASE]._ns_loaded, 1,
683 args->dotrace) && args->doexit)
684 /* We cannot start the application. Abort now. */
685 _exit (1);
686 }
687
688
689 static inline struct link_map *
690 find_needed (const char *name)
691 {
692 struct r_scope_elem *scope = &GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_searchlist;
693 unsigned int n = scope->r_nlist;
694
695 while (n-- > 0)
696 if (_dl_name_match_p (name, scope->r_list[n]))
697 return scope->r_list[n];
698
699 /* Should never happen. */
700 return NULL;
701 }
702
703 static int
704 match_version (const char *string, struct link_map *map)
705 {
706 const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
707 ElfW(Verdef) *def;
708
709 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
710 if (map->l_info[VERDEFTAG] == NULL)
711 /* The file has no symbol versioning. */
712 return 0;
713
714 def = (ElfW(Verdef) *) ((char *) map->l_addr
715 + map->l_info[VERDEFTAG]->d_un.d_ptr);
716 while (1)
717 {
718 ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);
719
720 /* Compare the version strings. */
721 if (strcmp (string, strtab + aux->vda_name) == 0)
722 /* Bingo! */
723 return 1;
724
725 /* If no more definitions we failed to find what we want. */
726 if (def->vd_next == 0)
727 break;
728
729 /* Next definition. */
730 def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
731 }
732
733 return 0;
734 }
735
736 static bool tls_init_tp_called;
737
738 static void *
739 init_tls (void)
740 {
741 /* Number of elements in the static TLS block. */
742 GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
743
744 /* Do not do this twice. The audit interface might have required
745 the DTV interfaces to be set up early. */
746 if (GL(dl_initial_dtv) != NULL)
747 return NULL;
748
749 /* Allocate the array which contains the information about the
750 dtv slots. We allocate a few entries more than needed to
751 avoid the need for reallocation. */
752 size_t nelem = GL(dl_tls_max_dtv_idx) + 1 + TLS_SLOTINFO_SURPLUS;
753
754 /* Allocate. */
755 GL(dl_tls_dtv_slotinfo_list) = (struct dtv_slotinfo_list *)
756 calloc (sizeof (struct dtv_slotinfo_list)
757 + nelem * sizeof (struct dtv_slotinfo), 1);
758 /* No need to check the return value. If memory allocation failed
759 the program would have been terminated. */
760
761 struct dtv_slotinfo *slotinfo = GL(dl_tls_dtv_slotinfo_list)->slotinfo;
762 GL(dl_tls_dtv_slotinfo_list)->len = nelem;
763 GL(dl_tls_dtv_slotinfo_list)->next = NULL;
764
765 /* Fill in the information from the loaded modules. No namespace
766 but the base one can be filled at this time. */
767 assert (GL(dl_ns)[LM_ID_BASE + 1]._ns_loaded == NULL);
768 int i = 0;
769 for (struct link_map *l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; l != NULL;
770 l = l->l_next)
771 if (l->l_tls_blocksize != 0)
772 {
773 /* This is a module with TLS data. Store the map reference.
774 The generation counter is zero. */
775 slotinfo[i].map = l;
776 /* slotinfo[i].gen = 0; */
777 ++i;
778 }
779 assert (i == GL(dl_tls_max_dtv_idx));
780
781 /* Compute the TLS offsets for the various blocks. */
782 _dl_determine_tlsoffset ();
783
784 /* Construct the static TLS block and the dtv for the initial
785 thread. For some platforms this will include allocating memory
786 for the thread descriptor. The memory for the TLS block will
787 never be freed. It should be allocated accordingly. The dtv
788 array can be changed if dynamic loading requires it. */
789 void *tcbp = _dl_allocate_tls_storage ();
790 if (tcbp == NULL)
791 _dl_fatal_printf ("\
792 cannot allocate TLS data structures for initial thread\n");
793
794 /* Store for detection of the special case by __tls_get_addr
795 so it knows not to pass this dtv to the normal realloc. */
796 GL(dl_initial_dtv) = GET_DTV (tcbp);
797
798 /* And finally install it for the main thread. */
799 const char *lossage = TLS_INIT_TP (tcbp);
800 if (__glibc_unlikely (lossage != NULL))
801 _dl_fatal_printf ("cannot set up thread-local storage: %s\n", lossage);
802 tls_init_tp_called = true;
803
804 return tcbp;
805 }
806
807 static unsigned int
808 do_preload (const char *fname, struct link_map *main_map, const char *where)
809 {
810 const char *objname;
811 const char *err_str = NULL;
812 struct map_args args;
813 bool malloced;
814
815 args.str = fname;
816 args.loader = main_map;
817 args.mode = __RTLD_SECURE;
818
819 unsigned int old_nloaded = GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
820
821 (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit, &args);
822 if (__glibc_unlikely (err_str != NULL))
823 {
824 _dl_error_printf ("\
825 ERROR: ld.so: object '%s' from %s cannot be preloaded (%s): ignored.\n",
826 fname, where, err_str);
827 /* No need to call free, this is still before
828 the libc's malloc is used. */
829 }
830 else if (GL(dl_ns)[LM_ID_BASE]._ns_nloaded != old_nloaded)
831 /* It is no duplicate. */
832 return 1;
833
834 /* Nothing loaded. */
835 return 0;
836 }
837
838 #if defined SHARED && defined _LIBC_REENTRANT \
839 && defined __rtld_lock_default_lock_recursive
840 static void
841 rtld_lock_default_lock_recursive (void *lock)
842 {
843 __rtld_lock_default_lock_recursive (lock);
844 }
845
846 static void
847 rtld_lock_default_unlock_recursive (void *lock)
848 {
849 __rtld_lock_default_unlock_recursive (lock);
850 }
851 #endif
852
853
854 static void
855 security_init (void)
856 {
857 /* Set up the stack checker's canary. */
858 uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
859 #ifdef THREAD_SET_STACK_GUARD
860 THREAD_SET_STACK_GUARD (stack_chk_guard);
861 #else
862 __stack_chk_guard = stack_chk_guard;
863 #endif
864
865 /* Set up the pointer guard as well, if necessary. */
866 uintptr_t pointer_chk_guard
867 = _dl_setup_pointer_guard (_dl_random, stack_chk_guard);
868 #ifdef THREAD_SET_POINTER_GUARD
869 THREAD_SET_POINTER_GUARD (pointer_chk_guard);
870 #endif
871 __pointer_chk_guard_local = pointer_chk_guard;
872
873 /* We do not need the _dl_random value anymore. The less
874 information we leave behind, the better, so clear the
875 variable. */
876 _dl_random = NULL;
877 }
878
879 #include <setup-vdso.h>
880
881 /* The library search path. */
882 static const char *library_path attribute_relro;
883 /* The list preloaded objects. */
884 static const char *preloadlist attribute_relro;
885 /* Nonzero if information about versions has to be printed. */
886 static int version_info attribute_relro;
887 /* The preload list passed as a command argument. */
888 static const char *preloadarg attribute_relro;
889
890 /* The LD_PRELOAD environment variable gives list of libraries
891 separated by white space or colons that are loaded before the
892 executable's dependencies and prepended to the global scope list.
893 (If the binary is running setuid all elements containing a '/' are
894 ignored since it is insecure.) Return the number of preloads
895 performed. Ditto for --preload command argument. */
896 unsigned int
897 handle_preload_list (const char *preloadlist, struct link_map *main_map,
898 const char *where)
899 {
900 unsigned int npreloads = 0;
901 const char *p = preloadlist;
902 char fname[SECURE_PATH_LIMIT];
903
904 while (*p != '\0')
905 {
906 /* Split preload list at space/colon. */
907 size_t len = strcspn (p, " :");
908 if (len > 0 && len < sizeof (fname))
909 {
910 memcpy (fname, p, len);
911 fname[len] = '\0';
912 }
913 else
914 fname[0] = '\0';
915
916 /* Skip over the substring and the following delimiter. */
917 p += len;
918 if (*p != '\0')
919 ++p;
920
921 if (dso_name_valid_for_suid (fname))
922 npreloads += do_preload (fname, main_map, where);
923 }
924 return npreloads;
925 }
926
927 /* Called if the audit DSO cannot be used: if it does not have the
928 appropriate interfaces, or it expects a more recent version library
929 version than what the dynamic linker provides. */
930 static void
931 unload_audit_module (struct link_map *map, int original_tls_idx)
932 {
933 #ifndef NDEBUG
934 Lmid_t ns = map->l_ns;
935 #endif
936 _dl_close (map);
937
938 /* Make sure the namespace has been cleared entirely. */
939 assert (GL(dl_ns)[ns]._ns_loaded == NULL);
940 assert (GL(dl_ns)[ns]._ns_nloaded == 0);
941
942 GL(dl_tls_max_dtv_idx) = original_tls_idx;
943 }
944
945 /* Called to print an error message if loading of an audit module
946 failed. */
947 static void
948 report_audit_module_load_error (const char *name, const char *err_str,
949 bool malloced)
950 {
951 _dl_error_printf ("\
952 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
953 name, err_str);
954 if (malloced)
955 free ((char *) err_str);
956 }
957
958 /* Load one audit module. */
959 static void
960 load_audit_module (const char *name, struct audit_ifaces **last_audit)
961 {
962 int original_tls_idx = GL(dl_tls_max_dtv_idx);
963
964 struct dlmopen_args dlmargs;
965 dlmargs.fname = name;
966 dlmargs.map = NULL;
967
968 const char *objname;
969 const char *err_str = NULL;
970 bool malloced;
971 _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit, &dlmargs);
972 if (__glibc_unlikely (err_str != NULL))
973 {
974 report_audit_module_load_error (name, err_str, malloced);
975 return;
976 }
977
978 struct lookup_args largs;
979 largs.name = "la_version";
980 largs.map = dlmargs.map;
981 _dl_catch_error (&objname, &err_str, &malloced, lookup_doit, &largs);
982 if (__glibc_likely (err_str != NULL))
983 {
984 unload_audit_module (dlmargs.map, original_tls_idx);
985 report_audit_module_load_error (name, err_str, malloced);
986 return;
987 }
988
989 unsigned int (*laversion) (unsigned int) = largs.result;
990
991 /* A null symbol indicates that something is very wrong with the
992 loaded object because defined symbols are supposed to have a
993 valid, non-null address. */
994 assert (laversion != NULL);
995
996 unsigned int lav = laversion (LAV_CURRENT);
997 if (lav == 0)
998 {
999 /* Only print an error message if debugging because this can
1000 happen deliberately. */
1001 if (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
1002 _dl_debug_printf ("\
1003 file=%s [%lu]; audit interface function la_version returned zero; ignored.\n",
1004 dlmargs.map->l_name, dlmargs.map->l_ns);
1005 unload_audit_module (dlmargs.map, original_tls_idx);
1006 return;
1007 }
1008
1009 if (lav > LAV_CURRENT)
1010 {
1011 _dl_debug_printf ("\
1012 ERROR: audit interface '%s' requires version %d (maximum supported version %d); ignored.\n",
1013 name, lav, LAV_CURRENT);
1014 unload_audit_module (dlmargs.map, original_tls_idx);
1015 return;
1016 }
1017
1018 enum { naudit_ifaces = 8 };
1019 union
1020 {
1021 struct audit_ifaces ifaces;
1022 void (*fptr[naudit_ifaces]) (void);
1023 } *newp = malloc (sizeof (*newp));
1024 if (newp == NULL)
1025 _dl_fatal_printf ("Out of memory while loading audit modules\n");
1026
1027 /* Names of the auditing interfaces. All in one
1028 long string. */
1029 static const char audit_iface_names[] =
1030 "la_activity\0"
1031 "la_objsearch\0"
1032 "la_objopen\0"
1033 "la_preinit\0"
1034 #if __ELF_NATIVE_CLASS == 32
1035 "la_symbind32\0"
1036 #elif __ELF_NATIVE_CLASS == 64
1037 "la_symbind64\0"
1038 #else
1039 # error "__ELF_NATIVE_CLASS must be defined"
1040 #endif
1041 #define STRING(s) __STRING (s)
1042 "la_" STRING (ARCH_LA_PLTENTER) "\0"
1043 "la_" STRING (ARCH_LA_PLTEXIT) "\0"
1044 "la_objclose\0";
1045 unsigned int cnt = 0;
1046 const char *cp = audit_iface_names;
1047 do
1048 {
1049 largs.name = cp;
1050 _dl_catch_error (&objname, &err_str, &malloced, lookup_doit, &largs);
1051
1052 /* Store the pointer. */
1053 if (err_str == NULL && largs.result != NULL)
1054 newp->fptr[cnt] = largs.result;
1055 else
1056 newp->fptr[cnt] = NULL;
1057 ++cnt;
1058
1059 cp = rawmemchr (cp, '\0') + 1;
1060 }
1061 while (*cp != '\0');
1062 assert (cnt == naudit_ifaces);
1063
1064 /* Now append the new auditing interface to the list. */
1065 newp->ifaces.next = NULL;
1066 if (*last_audit == NULL)
1067 *last_audit = GLRO(dl_audit) = &newp->ifaces;
1068 else
1069 *last_audit = (*last_audit)->next = &newp->ifaces;
1070
1071 /* The dynamic linker link map is statically allocated, so the
1072 cookie in _dl_new_object has not happened. */
1073 link_map_audit_state (&GL (dl_rtld_map), GLRO (dl_naudit))->cookie
1074 = (intptr_t) &GL (dl_rtld_map);
1075
1076 ++GLRO(dl_naudit);
1077
1078 /* Mark the DSO as being used for auditing. */
1079 dlmargs.map->l_auditing = 1;
1080 }
1081
1082 /* Notify the the audit modules that the object MAP has already been
1083 loaded. */
1084 static void
1085 notify_audit_modules_of_loaded_object (struct link_map *map)
1086 {
1087 struct audit_ifaces *afct = GLRO(dl_audit);
1088 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1089 {
1090 if (afct->objopen != NULL)
1091 {
1092 struct auditstate *state = link_map_audit_state (map, cnt);
1093 state->bindflags = afct->objopen (map, LM_ID_BASE, &state->cookie);
1094 map->l_audit_any_plt |= state->bindflags != 0;
1095 }
1096
1097 afct = afct->next;
1098 }
1099 }
1100
1101 /* Load all audit modules. */
1102 static void
1103 load_audit_modules (struct link_map *main_map, struct audit_list *audit_list)
1104 {
1105 struct audit_ifaces *last_audit = NULL;
1106
1107 while (true)
1108 {
1109 const char *name = audit_list_next (audit_list);
1110 if (name == NULL)
1111 break;
1112 load_audit_module (name, &last_audit);
1113 }
1114
1115 /* Notify audit modules of the initially loaded modules (the main
1116 program and the dynamic linker itself). */
1117 if (GLRO(dl_naudit) > 0)
1118 {
1119 notify_audit_modules_of_loaded_object (main_map);
1120 notify_audit_modules_of_loaded_object (&GL(dl_rtld_map));
1121 }
1122 }
1123
1124 static void
1125 dl_main (const ElfW(Phdr) *phdr,
1126 ElfW(Word) phnum,
1127 ElfW(Addr) *user_entry,
1128 ElfW(auxv_t) *auxv)
1129 {
1130 const ElfW(Phdr) *ph;
1131 enum mode mode;
1132 struct link_map *main_map;
1133 size_t file_size;
1134 char *file;
1135 bool has_interp = false;
1136 unsigned int i;
1137 bool prelinked = false;
1138 bool rtld_is_main = false;
1139 void *tcbp = NULL;
1140
1141 struct audit_list audit_list;
1142 audit_list_init (&audit_list);
1143
1144 GL(dl_init_static_tls) = &_dl_nothread_init_static_tls;
1145
1146 #if defined SHARED && defined _LIBC_REENTRANT \
1147 && defined __rtld_lock_default_lock_recursive
1148 GL(dl_rtld_lock_recursive) = rtld_lock_default_lock_recursive;
1149 GL(dl_rtld_unlock_recursive) = rtld_lock_default_unlock_recursive;
1150 #endif
1151
1152 /* The explicit initialization here is cheaper than processing the reloc
1153 in the _rtld_local definition's initializer. */
1154 GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable;
1155
1156 /* Process the environment variable which control the behaviour. */
1157 process_envvars (&mode, &audit_list);
1158
1159 #ifndef HAVE_INLINED_SYSCALLS
1160 /* Set up a flag which tells we are just starting. */
1161 _dl_starting_up = 1;
1162 #endif
1163
1164 if (*user_entry == (ElfW(Addr)) ENTRY_POINT)
1165 {
1166 /* Ho ho. We are not the program interpreter! We are the program
1167 itself! This means someone ran ld.so as a command. Well, that
1168 might be convenient to do sometimes. We support it by
1169 interpreting the args like this:
1170
1171 ld.so PROGRAM ARGS...
1172
1173 The first argument is the name of a file containing an ELF
1174 executable we will load and run with the following arguments.
1175 To simplify life here, PROGRAM is searched for using the
1176 normal rules for shared objects, rather than $PATH or anything
1177 like that. We just load it and use its entry point; we don't
1178 pay attention to its PT_INTERP command (we are the interpreter
1179 ourselves). This is an easy way to test a new ld.so before
1180 installing it. */
1181 rtld_is_main = true;
1182
1183 /* Note the place where the dynamic linker actually came from. */
1184 GL(dl_rtld_map).l_name = rtld_progname;
1185
1186 while (_dl_argc > 1)
1187 if (! strcmp (_dl_argv[1], "--list"))
1188 {
1189 mode = list;
1190 GLRO(dl_lazy) = -1; /* This means do no dependency analysis. */
1191
1192 ++_dl_skip_args;
1193 --_dl_argc;
1194 ++_dl_argv;
1195 }
1196 else if (! strcmp (_dl_argv[1], "--verify"))
1197 {
1198 mode = verify;
1199
1200 ++_dl_skip_args;
1201 --_dl_argc;
1202 ++_dl_argv;
1203 }
1204 else if (! strcmp (_dl_argv[1], "--inhibit-cache"))
1205 {
1206 GLRO(dl_inhibit_cache) = 1;
1207 ++_dl_skip_args;
1208 --_dl_argc;
1209 ++_dl_argv;
1210 }
1211 else if (! strcmp (_dl_argv[1], "--library-path")
1212 && _dl_argc > 2)
1213 {
1214 library_path = _dl_argv[2];
1215
1216 _dl_skip_args += 2;
1217 _dl_argc -= 2;
1218 _dl_argv += 2;
1219 }
1220 else if (! strcmp (_dl_argv[1], "--inhibit-rpath")
1221 && _dl_argc > 2)
1222 {
1223 GLRO(dl_inhibit_rpath) = _dl_argv[2];
1224
1225 _dl_skip_args += 2;
1226 _dl_argc -= 2;
1227 _dl_argv += 2;
1228 }
1229 else if (! strcmp (_dl_argv[1], "--audit") && _dl_argc > 2)
1230 {
1231 audit_list_add_string (&audit_list, _dl_argv[2]);
1232
1233 _dl_skip_args += 2;
1234 _dl_argc -= 2;
1235 _dl_argv += 2;
1236 }
1237 else if (! strcmp (_dl_argv[1], "--preload") && _dl_argc > 2)
1238 {
1239 preloadarg = _dl_argv[2];
1240 _dl_skip_args += 2;
1241 _dl_argc -= 2;
1242 _dl_argv += 2;
1243 }
1244 else
1245 break;
1246
1247 /* If we have no further argument the program was called incorrectly.
1248 Grant the user some education. */
1249 if (_dl_argc < 2)
1250 _dl_fatal_printf ("\
1251 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
1252 You have invoked `ld.so', the helper program for shared library executables.\n\
1253 This program usually lives in the file `/lib/ld.so', and special directives\n\
1254 in executable files using ELF shared libraries tell the system's program\n\
1255 loader to load the helper program from this file. This helper program loads\n\
1256 the shared libraries needed by the program executable, prepares the program\n\
1257 to run, and runs it. You may invoke this helper program directly from the\n\
1258 command line to load and run an ELF executable file; this is like executing\n\
1259 that file itself, but always uses this helper program from the file you\n\
1260 specified, instead of the helper program file specified in the executable\n\
1261 file you run. This is mostly of use for maintainers to test new versions\n\
1262 of this helper program; chances are you did not intend to run this program.\n\
1263 \n\
1264 --list list all dependencies and how they are resolved\n\
1265 --verify verify that given object really is a dynamically linked\n\
1266 object we can handle\n\
1267 --inhibit-cache Do not use " LD_SO_CACHE "\n\
1268 --library-path PATH use given PATH instead of content of the environment\n\
1269 variable LD_LIBRARY_PATH\n\
1270 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
1271 in LIST\n\
1272 --audit LIST use objects named in LIST as auditors\n\
1273 --preload LIST preload objects named in LIST\n");
1274
1275 ++_dl_skip_args;
1276 --_dl_argc;
1277 ++_dl_argv;
1278
1279 /* The initialization of _dl_stack_flags done below assumes the
1280 executable's PT_GNU_STACK may have been honored by the kernel, and
1281 so a PT_GNU_STACK with PF_X set means the stack started out with
1282 execute permission. However, this is not really true if the
1283 dynamic linker is the executable the kernel loaded. For this
1284 case, we must reinitialize _dl_stack_flags to match the dynamic
1285 linker itself. If the dynamic linker was built with a
1286 PT_GNU_STACK, then the kernel may have loaded us with a
1287 nonexecutable stack that we will have to make executable when we
1288 load the program below unless it has a PT_GNU_STACK indicating
1289 nonexecutable stack is ok. */
1290
1291 for (ph = phdr; ph < &phdr[phnum]; ++ph)
1292 if (ph->p_type == PT_GNU_STACK)
1293 {
1294 GL(dl_stack_flags) = ph->p_flags;
1295 break;
1296 }
1297
1298 if (__builtin_expect (mode, normal) == verify)
1299 {
1300 const char *objname;
1301 const char *err_str = NULL;
1302 struct map_args args;
1303 bool malloced;
1304
1305 args.str = rtld_progname;
1306 args.loader = NULL;
1307 args.mode = __RTLD_OPENEXEC;
1308 (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit,
1309 &args);
1310 if (__glibc_unlikely (err_str != NULL))
1311 /* We don't free the returned string, the programs stops
1312 anyway. */
1313 _exit (EXIT_FAILURE);
1314 }
1315 else
1316 {
1317 RTLD_TIMING_VAR (start);
1318 rtld_timer_start (&start);
1319 _dl_map_object (NULL, rtld_progname, lt_executable, 0,
1320 __RTLD_OPENEXEC, LM_ID_BASE);
1321 rtld_timer_stop (&load_time, start);
1322 }
1323
1324 /* Now the map for the main executable is available. */
1325 main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
1326
1327 if (__builtin_expect (mode, normal) == normal
1328 && GL(dl_rtld_map).l_info[DT_SONAME] != NULL
1329 && main_map->l_info[DT_SONAME] != NULL
1330 && strcmp ((const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1331 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val,
1332 (const char *) D_PTR (main_map, l_info[DT_STRTAB])
1333 + main_map->l_info[DT_SONAME]->d_un.d_val) == 0)
1334 _dl_fatal_printf ("loader cannot load itself\n");
1335
1336 phdr = main_map->l_phdr;
1337 phnum = main_map->l_phnum;
1338 /* We overwrite here a pointer to a malloc()ed string. But since
1339 the malloc() implementation used at this point is the dummy
1340 implementations which has no real free() function it does not
1341 makes sense to free the old string first. */
1342 main_map->l_name = (char *) "";
1343 *user_entry = main_map->l_entry;
1344
1345 #ifdef HAVE_AUX_VECTOR
1346 /* Adjust the on-stack auxiliary vector so that it looks like the
1347 binary was executed directly. */
1348 for (ElfW(auxv_t) *av = auxv; av->a_type != AT_NULL; av++)
1349 switch (av->a_type)
1350 {
1351 case AT_PHDR:
1352 av->a_un.a_val = (uintptr_t) phdr;
1353 break;
1354 case AT_PHNUM:
1355 av->a_un.a_val = phnum;
1356 break;
1357 case AT_ENTRY:
1358 av->a_un.a_val = *user_entry;
1359 break;
1360 case AT_EXECFN:
1361 av->a_un.a_val = (uintptr_t) _dl_argv[0];
1362 break;
1363 }
1364 #endif
1365 }
1366 else
1367 {
1368 /* Create a link_map for the executable itself.
1369 This will be what dlopen on "" returns. */
1370 main_map = _dl_new_object ((char *) "", "", lt_executable, NULL,
1371 __RTLD_OPENEXEC, LM_ID_BASE);
1372 assert (main_map != NULL);
1373 main_map->l_phdr = phdr;
1374 main_map->l_phnum = phnum;
1375 main_map->l_entry = *user_entry;
1376
1377 /* Even though the link map is not yet fully initialized we can add
1378 it to the map list since there are no possible users running yet. */
1379 _dl_add_to_namespace_list (main_map, LM_ID_BASE);
1380 assert (main_map == GL(dl_ns)[LM_ID_BASE]._ns_loaded);
1381
1382 /* At this point we are in a bit of trouble. We would have to
1383 fill in the values for l_dev and l_ino. But in general we
1384 do not know where the file is. We also do not handle AT_EXECFD
1385 even if it would be passed up.
1386
1387 We leave the values here defined to 0. This is normally no
1388 problem as the program code itself is normally no shared
1389 object and therefore cannot be loaded dynamically. Nothing
1390 prevent the use of dynamic binaries and in these situations
1391 we might get problems. We might not be able to find out
1392 whether the object is already loaded. But since there is no
1393 easy way out and because the dynamic binary must also not
1394 have an SONAME we ignore this program for now. If it becomes
1395 a problem we can force people using SONAMEs. */
1396
1397 /* We delay initializing the path structure until we got the dynamic
1398 information for the program. */
1399 }
1400
1401 main_map->l_map_end = 0;
1402 main_map->l_text_end = 0;
1403 /* Perhaps the executable has no PT_LOAD header entries at all. */
1404 main_map->l_map_start = ~0;
1405 /* And it was opened directly. */
1406 ++main_map->l_direct_opencount;
1407
1408 /* Scan the program header table for the dynamic section. */
1409 for (ph = phdr; ph < &phdr[phnum]; ++ph)
1410 switch (ph->p_type)
1411 {
1412 case PT_PHDR:
1413 /* Find out the load address. */
1414 main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
1415 break;
1416 case PT_DYNAMIC:
1417 /* This tells us where to find the dynamic section,
1418 which tells us everything we need to do. */
1419 main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
1420 break;
1421 case PT_INTERP:
1422 /* This "interpreter segment" was used by the program loader to
1423 find the program interpreter, which is this program itself, the
1424 dynamic linker. We note what name finds us, so that a future
1425 dlopen call or DT_NEEDED entry, for something that wants to link
1426 against the dynamic linker as a shared library, will know that
1427 the shared object is already loaded. */
1428 _dl_rtld_libname.name = ((const char *) main_map->l_addr
1429 + ph->p_vaddr);
1430 /* _dl_rtld_libname.next = NULL; Already zero. */
1431 GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
1432
1433 /* Ordinarilly, we would get additional names for the loader from
1434 our DT_SONAME. This can't happen if we were actually linked as
1435 a static executable (detect this case when we have no DYNAMIC).
1436 If so, assume the filename component of the interpreter path to
1437 be our SONAME, and add it to our name list. */
1438 if (GL(dl_rtld_map).l_ld == NULL)
1439 {
1440 const char *p = NULL;
1441 const char *cp = _dl_rtld_libname.name;
1442
1443 /* Find the filename part of the path. */
1444 while (*cp != '\0')
1445 if (*cp++ == '/')
1446 p = cp;
1447
1448 if (p != NULL)
1449 {
1450 _dl_rtld_libname2.name = p;
1451 /* _dl_rtld_libname2.next = NULL; Already zero. */
1452 _dl_rtld_libname.next = &_dl_rtld_libname2;
1453 }
1454 }
1455
1456 has_interp = true;
1457 break;
1458 case PT_LOAD:
1459 {
1460 ElfW(Addr) mapstart;
1461 ElfW(Addr) allocend;
1462
1463 /* Remember where the main program starts in memory. */
1464 mapstart = (main_map->l_addr
1465 + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
1466 if (main_map->l_map_start > mapstart)
1467 main_map->l_map_start = mapstart;
1468
1469 /* Also where it ends. */
1470 allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz;
1471 if (main_map->l_map_end < allocend)
1472 main_map->l_map_end = allocend;
1473 if ((ph->p_flags & PF_X) && allocend > main_map->l_text_end)
1474 main_map->l_text_end = allocend;
1475 }
1476 break;
1477
1478 case PT_TLS:
1479 if (ph->p_memsz > 0)
1480 {
1481 /* Note that in the case the dynamic linker we duplicate work
1482 here since we read the PT_TLS entry already in
1483 _dl_start_final. But the result is repeatable so do not
1484 check for this special but unimportant case. */
1485 main_map->l_tls_blocksize = ph->p_memsz;
1486 main_map->l_tls_align = ph->p_align;
1487 if (ph->p_align == 0)
1488 main_map->l_tls_firstbyte_offset = 0;
1489 else
1490 main_map->l_tls_firstbyte_offset = (ph->p_vaddr
1491 & (ph->p_align - 1));
1492 main_map->l_tls_initimage_size = ph->p_filesz;
1493 main_map->l_tls_initimage = (void *) ph->p_vaddr;
1494
1495 /* This image gets the ID one. */
1496 GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1;
1497 }
1498 break;
1499
1500 case PT_GNU_STACK:
1501 GL(dl_stack_flags) = ph->p_flags;
1502 break;
1503
1504 case PT_GNU_RELRO:
1505 main_map->l_relro_addr = ph->p_vaddr;
1506 main_map->l_relro_size = ph->p_memsz;
1507 break;
1508
1509 case PT_NOTE:
1510 if (_rtld_process_pt_note (main_map, ph))
1511 _dl_error_printf ("\
1512 ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
1513 break;
1514 }
1515
1516 /* Adjust the address of the TLS initialization image in case
1517 the executable is actually an ET_DYN object. */
1518 if (main_map->l_tls_initimage != NULL)
1519 main_map->l_tls_initimage
1520 = (char *) main_map->l_tls_initimage + main_map->l_addr;
1521 if (! main_map->l_map_end)
1522 main_map->l_map_end = ~0;
1523 if (! main_map->l_text_end)
1524 main_map->l_text_end = ~0;
1525 if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name)
1526 {
1527 /* We were invoked directly, so the program might not have a
1528 PT_INTERP. */
1529 _dl_rtld_libname.name = GL(dl_rtld_map).l_name;
1530 /* _dl_rtld_libname.next = NULL; Already zero. */
1531 GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
1532 }
1533 else
1534 assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
1535
1536 /* If the current libname is different from the SONAME, add the
1537 latter as well. */
1538 if (GL(dl_rtld_map).l_info[DT_SONAME] != NULL
1539 && strcmp (GL(dl_rtld_map).l_libname->name,
1540 (const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1541 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val) != 0)
1542 {
1543 static struct libname_list newname;
1544 newname.name = ((char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1545 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_ptr);
1546 newname.next = NULL;
1547 newname.dont_free = 1;
1548
1549 assert (GL(dl_rtld_map).l_libname->next == NULL);
1550 GL(dl_rtld_map).l_libname->next = &newname;
1551 }
1552 /* The ld.so must be relocated since otherwise loading audit modules
1553 will fail since they reuse the very same ld.so. */
1554 assert (GL(dl_rtld_map).l_relocated);
1555
1556 if (! rtld_is_main)
1557 {
1558 /* Extract the contents of the dynamic section for easy access. */
1559 elf_get_dynamic_info (main_map, NULL);
1560 /* Set up our cache of pointers into the hash table. */
1561 _dl_setup_hash (main_map);
1562 }
1563
1564 if (__builtin_expect (mode, normal) == verify)
1565 {
1566 /* We were called just to verify that this is a dynamic
1567 executable using us as the program interpreter. Exit with an
1568 error if we were not able to load the binary or no interpreter
1569 is specified (i.e., this is no dynamically linked binary. */
1570 if (main_map->l_ld == NULL)
1571 _exit (1);
1572
1573 /* We allow here some platform specific code. */
1574 #ifdef DISTINGUISH_LIB_VERSIONS
1575 DISTINGUISH_LIB_VERSIONS;
1576 #endif
1577 _exit (has_interp ? 0 : 2);
1578 }
1579
1580 struct link_map **first_preload = &GL(dl_rtld_map).l_next;
1581 /* Set up the data structures for the system-supplied DSO early,
1582 so they can influence _dl_init_paths. */
1583 setup_vdso (main_map, &first_preload);
1584
1585 /* With vDSO setup we can initialize the function pointers. */
1586 setup_vdso_pointers ();
1587
1588 #ifdef DL_SYSDEP_OSCHECK
1589 DL_SYSDEP_OSCHECK (_dl_fatal_printf);
1590 #endif
1591
1592 /* Initialize the data structures for the search paths for shared
1593 objects. */
1594 _dl_init_paths (library_path);
1595
1596 /* Initialize _r_debug. */
1597 struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr,
1598 LM_ID_BASE);
1599 r->r_state = RT_CONSISTENT;
1600
1601 /* Put the link_map for ourselves on the chain so it can be found by
1602 name. Note that at this point the global chain of link maps contains
1603 exactly one element, which is pointed to by dl_loaded. */
1604 if (! GL(dl_rtld_map).l_name)
1605 /* If not invoked directly, the dynamic linker shared object file was
1606 found by the PT_INTERP name. */
1607 GL(dl_rtld_map).l_name = (char *) GL(dl_rtld_map).l_libname->name;
1608 GL(dl_rtld_map).l_type = lt_library;
1609 main_map->l_next = &GL(dl_rtld_map);
1610 GL(dl_rtld_map).l_prev = main_map;
1611 ++GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
1612 ++GL(dl_load_adds);
1613
1614 /* If LD_USE_LOAD_BIAS env variable has not been seen, default
1615 to not using bias for non-prelinked PIEs and libraries
1616 and using it for executables or prelinked PIEs or libraries. */
1617 if (GLRO(dl_use_load_bias) == (ElfW(Addr)) -2)
1618 GLRO(dl_use_load_bias) = main_map->l_addr == 0 ? -1 : 0;
1619
1620 /* Set up the program header information for the dynamic linker
1621 itself. It is needed in the dl_iterate_phdr callbacks. */
1622 const ElfW(Ehdr) *rtld_ehdr;
1623
1624 /* Starting from binutils-2.23, the linker will define the magic symbol
1625 __ehdr_start to point to our own ELF header if it is visible in a
1626 segment that also includes the phdrs. If that's not available, we use
1627 the old method that assumes the beginning of the file is part of the
1628 lowest-addressed PT_LOAD segment. */
1629 #ifdef HAVE_EHDR_START
1630 extern const ElfW(Ehdr) __ehdr_start __attribute__ ((visibility ("hidden")));
1631 rtld_ehdr = &__ehdr_start;
1632 #else
1633 rtld_ehdr = (void *) GL(dl_rtld_map).l_map_start;
1634 #endif
1635 assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr);
1636 assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr)));
1637
1638 const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff;
1639
1640 GL(dl_rtld_map).l_phdr = rtld_phdr;
1641 GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
1642
1643
1644 /* PT_GNU_RELRO is usually the last phdr. */
1645 size_t cnt = rtld_ehdr->e_phnum;
1646 while (cnt-- > 0)
1647 if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
1648 {
1649 GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
1650 GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
1651 break;
1652 }
1653
1654 /* Add the dynamic linker to the TLS list if it also uses TLS. */
1655 if (GL(dl_rtld_map).l_tls_blocksize != 0)
1656 /* Assign a module ID. Do this before loading any audit modules. */
1657 GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid ();
1658
1659 audit_list_add_dynamic_tag (&audit_list, main_map, DT_AUDIT);
1660 audit_list_add_dynamic_tag (&audit_list, main_map, DT_DEPAUDIT);
1661
1662 /* If we have auditing DSOs to load, do it now. */
1663 bool need_security_init = true;
1664 if (audit_list.length > 0)
1665 {
1666 /* Since we start using the auditing DSOs right away we need to
1667 initialize the data structures now. */
1668 tcbp = init_tls ();
1669
1670 /* Initialize security features. We need to do it this early
1671 since otherwise the constructors of the audit libraries will
1672 use different values (especially the pointer guard) and will
1673 fail later on. */
1674 security_init ();
1675 need_security_init = false;
1676
1677 load_audit_modules (main_map, &audit_list);
1678 }
1679
1680 /* Keep track of the currently loaded modules to count how many
1681 non-audit modules which use TLS are loaded. */
1682 size_t count_modids = _dl_count_modids ();
1683
1684 /* Set up debugging before the debugger is notified for the first time. */
1685 #ifdef ELF_MACHINE_DEBUG_SETUP
1686 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1687 ELF_MACHINE_DEBUG_SETUP (main_map, r);
1688 ELF_MACHINE_DEBUG_SETUP (&GL(dl_rtld_map), r);
1689 #else
1690 if (main_map->l_info[DT_DEBUG] != NULL)
1691 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1692 with the run-time address of the r_debug structure */
1693 main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
1694
1695 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1696 case you run gdb on the dynamic linker directly. */
1697 if (GL(dl_rtld_map).l_info[DT_DEBUG] != NULL)
1698 GL(dl_rtld_map).l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
1699 #endif
1700
1701 /* We start adding objects. */
1702 r->r_state = RT_ADD;
1703 _dl_debug_state ();
1704 LIBC_PROBE (init_start, 2, LM_ID_BASE, r);
1705
1706 /* Auditing checkpoint: we are ready to signal that the initial map
1707 is being constructed. */
1708 if (__glibc_unlikely (GLRO(dl_naudit) > 0))
1709 {
1710 struct audit_ifaces *afct = GLRO(dl_audit);
1711 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1712 {
1713 if (afct->activity != NULL)
1714 afct->activity (&link_map_audit_state (main_map, cnt)->cookie,
1715 LA_ACT_ADD);
1716
1717 afct = afct->next;
1718 }
1719 }
1720
1721 /* We have two ways to specify objects to preload: via environment
1722 variable and via the file /etc/ld.so.preload. The latter can also
1723 be used when security is enabled. */
1724 assert (*first_preload == NULL);
1725 struct link_map **preloads = NULL;
1726 unsigned int npreloads = 0;
1727
1728 if (__glibc_unlikely (preloadlist != NULL))
1729 {
1730 RTLD_TIMING_VAR (start);
1731 rtld_timer_start (&start);
1732 npreloads += handle_preload_list (preloadlist, main_map, "LD_PRELOAD");
1733 rtld_timer_accum (&load_time, start);
1734 }
1735
1736 if (__glibc_unlikely (preloadarg != NULL))
1737 {
1738 RTLD_TIMING_VAR (start);
1739 rtld_timer_start (&start);
1740 npreloads += handle_preload_list (preloadarg, main_map, "--preload");
1741 rtld_timer_accum (&load_time, start);
1742 }
1743
1744 /* There usually is no ld.so.preload file, it should only be used
1745 for emergencies and testing. So the open call etc should usually
1746 fail. Using access() on a non-existing file is faster than using
1747 open(). So we do this first. If it succeeds we do almost twice
1748 the work but this does not matter, since it is not for production
1749 use. */
1750 static const char preload_file[] = "/etc/ld.so.preload";
1751 if (__glibc_unlikely (__access (preload_file, R_OK) == 0))
1752 {
1753 /* Read the contents of the file. */
1754 file = _dl_sysdep_read_whole_file (preload_file, &file_size,
1755 PROT_READ | PROT_WRITE);
1756 if (__glibc_unlikely (file != MAP_FAILED))
1757 {
1758 /* Parse the file. It contains names of libraries to be loaded,
1759 separated by white spaces or `:'. It may also contain
1760 comments introduced by `#'. */
1761 char *problem;
1762 char *runp;
1763 size_t rest;
1764
1765 /* Eliminate comments. */
1766 runp = file;
1767 rest = file_size;
1768 while (rest > 0)
1769 {
1770 char *comment = memchr (runp, '#', rest);
1771 if (comment == NULL)
1772 break;
1773
1774 rest -= comment - runp;
1775 do
1776 *comment = ' ';
1777 while (--rest > 0 && *++comment != '\n');
1778 }
1779
1780 /* We have one problematic case: if we have a name at the end of
1781 the file without a trailing terminating characters, we cannot
1782 place the \0. Handle the case separately. */
1783 if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t'
1784 && file[file_size - 1] != '\n' && file[file_size - 1] != ':')
1785 {
1786 problem = &file[file_size];
1787 while (problem > file && problem[-1] != ' '
1788 && problem[-1] != '\t'
1789 && problem[-1] != '\n' && problem[-1] != ':')
1790 --problem;
1791
1792 if (problem > file)
1793 problem[-1] = '\0';
1794 }
1795 else
1796 {
1797 problem = NULL;
1798 file[file_size - 1] = '\0';
1799 }
1800
1801 RTLD_TIMING_VAR (start);
1802 rtld_timer_start (&start);
1803
1804 if (file != problem)
1805 {
1806 char *p;
1807 runp = file;
1808 while ((p = strsep (&runp, ": \t\n")) != NULL)
1809 if (p[0] != '\0')
1810 npreloads += do_preload (p, main_map, preload_file);
1811 }
1812
1813 if (problem != NULL)
1814 {
1815 char *p = strndupa (problem, file_size - (problem - file));
1816
1817 npreloads += do_preload (p, main_map, preload_file);
1818 }
1819
1820 rtld_timer_accum (&load_time, start);
1821
1822 /* We don't need the file anymore. */
1823 __munmap (file, file_size);
1824 }
1825 }
1826
1827 if (__glibc_unlikely (*first_preload != NULL))
1828 {
1829 /* Set up PRELOADS with a vector of the preloaded libraries. */
1830 struct link_map *l = *first_preload;
1831 preloads = __alloca (npreloads * sizeof preloads[0]);
1832 i = 0;
1833 do
1834 {
1835 preloads[i++] = l;
1836 l = l->l_next;
1837 } while (l);
1838 assert (i == npreloads);
1839 }
1840
1841 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
1842 specified some libraries to load, these are inserted before the actual
1843 dependencies in the executable's searchlist for symbol resolution. */
1844 {
1845 RTLD_TIMING_VAR (start);
1846 rtld_timer_start (&start);
1847 _dl_map_object_deps (main_map, preloads, npreloads, mode == trace, 0);
1848 rtld_timer_accum (&load_time, start);
1849 }
1850
1851 /* Mark all objects as being in the global scope. */
1852 for (i = main_map->l_searchlist.r_nlist; i > 0; )
1853 main_map->l_searchlist.r_list[--i]->l_global = 1;
1854
1855 /* Remove _dl_rtld_map from the chain. */
1856 GL(dl_rtld_map).l_prev->l_next = GL(dl_rtld_map).l_next;
1857 if (GL(dl_rtld_map).l_next != NULL)
1858 GL(dl_rtld_map).l_next->l_prev = GL(dl_rtld_map).l_prev;
1859
1860 for (i = 1; i < main_map->l_searchlist.r_nlist; ++i)
1861 if (main_map->l_searchlist.r_list[i] == &GL(dl_rtld_map))
1862 break;
1863
1864 bool rtld_multiple_ref = false;
1865 if (__glibc_likely (i < main_map->l_searchlist.r_nlist))
1866 {
1867 /* Some DT_NEEDED entry referred to the interpreter object itself, so
1868 put it back in the list of visible objects. We insert it into the
1869 chain in symbol search order because gdb uses the chain's order as
1870 its symbol search order. */
1871 rtld_multiple_ref = true;
1872
1873 GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1];
1874 if (__builtin_expect (mode, normal) == normal)
1875 {
1876 GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist
1877 ? main_map->l_searchlist.r_list[i + 1]
1878 : NULL);
1879 #ifdef NEED_DL_SYSINFO_DSO
1880 if (GLRO(dl_sysinfo_map) != NULL
1881 && GL(dl_rtld_map).l_prev->l_next == GLRO(dl_sysinfo_map)
1882 && GL(dl_rtld_map).l_next != GLRO(dl_sysinfo_map))
1883 GL(dl_rtld_map).l_prev = GLRO(dl_sysinfo_map);
1884 #endif
1885 }
1886 else
1887 /* In trace mode there might be an invisible object (which we
1888 could not find) after the previous one in the search list.
1889 In this case it doesn't matter much where we put the
1890 interpreter object, so we just initialize the list pointer so
1891 that the assertion below holds. */
1892 GL(dl_rtld_map).l_next = GL(dl_rtld_map).l_prev->l_next;
1893
1894 assert (GL(dl_rtld_map).l_prev->l_next == GL(dl_rtld_map).l_next);
1895 GL(dl_rtld_map).l_prev->l_next = &GL(dl_rtld_map);
1896 if (GL(dl_rtld_map).l_next != NULL)
1897 {
1898 assert (GL(dl_rtld_map).l_next->l_prev == GL(dl_rtld_map).l_prev);
1899 GL(dl_rtld_map).l_next->l_prev = &GL(dl_rtld_map);
1900 }
1901 }
1902
1903 /* Now let us see whether all libraries are available in the
1904 versions we need. */
1905 {
1906 struct version_check_args args;
1907 args.doexit = mode == normal;
1908 args.dotrace = mode == trace;
1909 _dl_receive_error (print_missing_version, version_check_doit, &args);
1910 }
1911
1912 /* We do not initialize any of the TLS functionality unless any of the
1913 initial modules uses TLS. This makes dynamic loading of modules with
1914 TLS impossible, but to support it requires either eagerly doing setup
1915 now or lazily doing it later. Doing it now makes us incompatible with
1916 an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
1917 used. Trying to do it lazily is too hairy to try when there could be
1918 multiple threads (from a non-TLS-using libpthread). */
1919 bool was_tls_init_tp_called = tls_init_tp_called;
1920 if (tcbp == NULL)
1921 tcbp = init_tls ();
1922
1923 if (__glibc_likely (need_security_init))
1924 /* Initialize security features. But only if we have not done it
1925 earlier. */
1926 security_init ();
1927
1928 if (__builtin_expect (mode, normal) != normal)
1929 {
1930 /* We were run just to list the shared libraries. It is
1931 important that we do this before real relocation, because the
1932 functions we call below for output may no longer work properly
1933 after relocation. */
1934 struct link_map *l;
1935
1936 if (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
1937 {
1938 struct r_scope_elem *scope = &main_map->l_searchlist;
1939
1940 for (i = 0; i < scope->r_nlist; i++)
1941 {
1942 l = scope->r_list [i];
1943 if (l->l_faked)
1944 {
1945 _dl_printf ("\t%s => not found\n", l->l_libname->name);
1946 continue;
1947 }
1948 if (_dl_name_match_p (GLRO(dl_trace_prelink), l))
1949 GLRO(dl_trace_prelink_map) = l;
1950 _dl_printf ("\t%s => %s (0x%0*Zx, 0x%0*Zx)",
1951 DSO_FILENAME (l->l_libname->name),
1952 DSO_FILENAME (l->l_name),
1953 (int) sizeof l->l_map_start * 2,
1954 (size_t) l->l_map_start,
1955 (int) sizeof l->l_addr * 2,
1956 (size_t) l->l_addr);
1957
1958 if (l->l_tls_modid)
1959 _dl_printf (" TLS(0x%Zx, 0x%0*Zx)\n", l->l_tls_modid,
1960 (int) sizeof l->l_tls_offset * 2,
1961 (size_t) l->l_tls_offset);
1962 else
1963 _dl_printf ("\n");
1964 }
1965 }
1966 else if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
1967 {
1968 /* Look through the dependencies of the main executable
1969 and determine which of them is not actually
1970 required. */
1971 struct link_map *l = main_map;
1972
1973 /* Relocate the main executable. */
1974 struct relocate_args args = { .l = l,
1975 .reloc_mode = ((GLRO(dl_lazy)
1976 ? RTLD_LAZY : 0)
1977 | __RTLD_NOIFUNC) };
1978 _dl_receive_error (print_unresolved, relocate_doit, &args);
1979
1980 /* This loop depends on the dependencies of the executable to
1981 correspond in number and order to the DT_NEEDED entries. */
1982 ElfW(Dyn) *dyn = main_map->l_ld;
1983 bool first = true;
1984 while (dyn->d_tag != DT_NULL)
1985 {
1986 if (dyn->d_tag == DT_NEEDED)
1987 {
1988 l = l->l_next;
1989 #ifdef NEED_DL_SYSINFO_DSO
1990 /* Skip the VDSO since it's not part of the list
1991 of objects we brought in via DT_NEEDED entries. */
1992 if (l == GLRO(dl_sysinfo_map))
1993 l = l->l_next;
1994 #endif
1995 if (!l->l_used)
1996 {
1997 if (first)
1998 {
1999 _dl_printf ("Unused direct dependencies:\n");
2000 first = false;
2001 }
2002
2003 _dl_printf ("\t%s\n", l->l_name);
2004 }
2005 }
2006
2007 ++dyn;
2008 }
2009
2010 _exit (first != true);
2011 }
2012 else if (! main_map->l_info[DT_NEEDED])
2013 _dl_printf ("\tstatically linked\n");
2014 else
2015 {
2016 for (l = main_map->l_next; l; l = l->l_next)
2017 if (l->l_faked)
2018 /* The library was not found. */
2019 _dl_printf ("\t%s => not found\n", l->l_libname->name);
2020 else if (strcmp (l->l_libname->name, l->l_name) == 0)
2021 _dl_printf ("\t%s (0x%0*Zx)\n", l->l_libname->name,
2022 (int) sizeof l->l_map_start * 2,
2023 (size_t) l->l_map_start);
2024 else
2025 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l->l_libname->name,
2026 l->l_name, (int) sizeof l->l_map_start * 2,
2027 (size_t) l->l_map_start);
2028 }
2029
2030 if (__builtin_expect (mode, trace) != trace)
2031 for (i = 1; i < (unsigned int) _dl_argc; ++i)
2032 {
2033 const ElfW(Sym) *ref = NULL;
2034 ElfW(Addr) loadbase;
2035 lookup_t result;
2036
2037 result = _dl_lookup_symbol_x (_dl_argv[i], main_map,
2038 &ref, main_map->l_scope,
2039 NULL, ELF_RTYPE_CLASS_PLT,
2040 DL_LOOKUP_ADD_DEPENDENCY, NULL);
2041
2042 loadbase = LOOKUP_VALUE_ADDRESS (result, false);
2043
2044 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
2045 _dl_argv[i],
2046 (int) sizeof ref->st_value * 2,
2047 (size_t) ref->st_value,
2048 (int) sizeof loadbase * 2, (size_t) loadbase);
2049 }
2050 else
2051 {
2052 /* If LD_WARN is set, warn about undefined symbols. */
2053 if (GLRO(dl_lazy) >= 0 && GLRO(dl_verbose))
2054 {
2055 /* We have to do symbol dependency testing. */
2056 struct relocate_args args;
2057 unsigned int i;
2058
2059 args.reloc_mode = ((GLRO(dl_lazy) ? RTLD_LAZY : 0)
2060 | __RTLD_NOIFUNC);
2061
2062 i = main_map->l_searchlist.r_nlist;
2063 while (i-- > 0)
2064 {
2065 struct link_map *l = main_map->l_initfini[i];
2066 if (l != &GL(dl_rtld_map) && ! l->l_faked)
2067 {
2068 args.l = l;
2069 _dl_receive_error (print_unresolved, relocate_doit,
2070 &args);
2071 }
2072 }
2073
2074 if ((GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
2075 && rtld_multiple_ref)
2076 {
2077 /* Mark the link map as not yet relocated again. */
2078 GL(dl_rtld_map).l_relocated = 0;
2079 _dl_relocate_object (&GL(dl_rtld_map),
2080 main_map->l_scope, __RTLD_NOIFUNC, 0);
2081 }
2082 }
2083 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
2084 if (version_info)
2085 {
2086 /* Print more information. This means here, print information
2087 about the versions needed. */
2088 int first = 1;
2089 struct link_map *map;
2090
2091 for (map = main_map; map != NULL; map = map->l_next)
2092 {
2093 const char *strtab;
2094 ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG];
2095 ElfW(Verneed) *ent;
2096
2097 if (dyn == NULL)
2098 continue;
2099
2100 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
2101 ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
2102
2103 if (first)
2104 {
2105 _dl_printf ("\n\tVersion information:\n");
2106 first = 0;
2107 }
2108
2109 _dl_printf ("\t%s:\n", DSO_FILENAME (map->l_name));
2110
2111 while (1)
2112 {
2113 ElfW(Vernaux) *aux;
2114 struct link_map *needed;
2115
2116 needed = find_needed (strtab + ent->vn_file);
2117 aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
2118
2119 while (1)
2120 {
2121 const char *fname = NULL;
2122
2123 if (needed != NULL
2124 && match_version (strtab + aux->vna_name,
2125 needed))
2126 fname = needed->l_name;
2127
2128 _dl_printf ("\t\t%s (%s) %s=> %s\n",
2129 strtab + ent->vn_file,
2130 strtab + aux->vna_name,
2131 aux->vna_flags & VER_FLG_WEAK
2132 ? "[WEAK] " : "",
2133 fname ?: "not found");
2134
2135 if (aux->vna_next == 0)
2136 /* No more symbols. */
2137 break;
2138
2139 /* Next symbol. */
2140 aux = (ElfW(Vernaux) *) ((char *) aux
2141 + aux->vna_next);
2142 }
2143
2144 if (ent->vn_next == 0)
2145 /* No more dependencies. */
2146 break;
2147
2148 /* Next dependency. */
2149 ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
2150 }
2151 }
2152 }
2153 }
2154
2155 _exit (0);
2156 }
2157
2158 if (main_map->l_info[ADDRIDX (DT_GNU_LIBLIST)]
2159 && ! __builtin_expect (GLRO(dl_profile) != NULL, 0)
2160 && ! __builtin_expect (GLRO(dl_dynamic_weak), 0))
2161 {
2162 ElfW(Lib) *liblist, *liblistend;
2163 struct link_map **r_list, **r_listend, *l;
2164 const char *strtab = (const void *) D_PTR (main_map, l_info[DT_STRTAB]);
2165
2166 assert (main_map->l_info[VALIDX (DT_GNU_LIBLISTSZ)] != NULL);
2167 liblist = (ElfW(Lib) *)
2168 main_map->l_info[ADDRIDX (DT_GNU_LIBLIST)]->d_un.d_ptr;
2169 liblistend = (ElfW(Lib) *)
2170 ((char *) liblist
2171 + main_map->l_info[VALIDX (DT_GNU_LIBLISTSZ)]->d_un.d_val);
2172 r_list = main_map->l_searchlist.r_list;
2173 r_listend = r_list + main_map->l_searchlist.r_nlist;
2174
2175 for (; r_list < r_listend && liblist < liblistend; r_list++)
2176 {
2177 l = *r_list;
2178
2179 if (l == main_map)
2180 continue;
2181
2182 /* If the library is not mapped where it should, fail. */
2183 if (l->l_addr)
2184 break;
2185
2186 /* Next, check if checksum matches. */
2187 if (l->l_info [VALIDX(DT_CHECKSUM)] == NULL
2188 || l->l_info [VALIDX(DT_CHECKSUM)]->d_un.d_val
2189 != liblist->l_checksum)
2190 break;
2191
2192 if (l->l_info [VALIDX(DT_GNU_PRELINKED)] == NULL
2193 || l->l_info [VALIDX(DT_GNU_PRELINKED)]->d_un.d_val
2194 != liblist->l_time_stamp)
2195 break;
2196
2197 if (! _dl_name_match_p (strtab + liblist->l_name, l))
2198 break;
2199
2200 ++liblist;
2201 }
2202
2203
2204 if (r_list == r_listend && liblist == liblistend)
2205 prelinked = true;
2206
2207 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
2208 _dl_debug_printf ("\nprelink checking: %s\n",
2209 prelinked ? "ok" : "failed");
2210 }
2211
2212
2213 /* Now set up the variable which helps the assembler startup code. */
2214 GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist = &main_map->l_searchlist;
2215
2216 /* Save the information about the original global scope list since
2217 we need it in the memory handling later. */
2218 GLRO(dl_initial_searchlist) = *GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist;
2219
2220 /* Remember the last search directory added at startup, now that
2221 malloc will no longer be the one from dl-minimal.c. As a side
2222 effect, this marks ld.so as initialized, so that the rtld_active
2223 function returns true from now on. */
2224 GLRO(dl_init_all_dirs) = GL(dl_all_dirs);
2225
2226 /* Print scope information. */
2227 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))
2228 {
2229 _dl_debug_printf ("\nInitial object scopes\n");
2230
2231 for (struct link_map *l = main_map; l != NULL; l = l->l_next)
2232 _dl_show_scope (l, 0);
2233 }
2234
2235 _rtld_main_check (main_map, _dl_argv[0]);
2236
2237 if (prelinked)
2238 {
2239 if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
2240 {
2241 ElfW(Rela) *conflict, *conflictend;
2242
2243 RTLD_TIMING_VAR (start);
2244 rtld_timer_start (&start);
2245
2246 assert (main_map->l_info [VALIDX (DT_GNU_CONFLICTSZ)] != NULL);
2247 conflict = (ElfW(Rela) *)
2248 main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)]->d_un.d_ptr;
2249 conflictend = (ElfW(Rela) *)
2250 ((char *) conflict
2251 + main_map->l_info [VALIDX (DT_GNU_CONFLICTSZ)]->d_un.d_val);
2252 _dl_resolve_conflicts (main_map, conflict, conflictend);
2253
2254 rtld_timer_stop (&relocate_time, start);
2255 }
2256
2257 /* The library defining malloc has already been relocated due to
2258 prelinking. Resolve the malloc symbols for the dynamic
2259 loader. */
2260 __rtld_malloc_init_real (main_map);
2261
2262 /* Mark all the objects so we know they have been already relocated. */
2263 for (struct link_map *l = main_map; l != NULL; l = l->l_next)
2264 {
2265 l->l_relocated = 1;
2266 if (l->l_relro_size)
2267 _dl_protect_relro (l);
2268
2269 /* Add object to slot information data if necessasy. */
2270 if (l->l_tls_blocksize != 0 && tls_init_tp_called)
2271 _dl_add_to_slotinfo (l, true);
2272 }
2273 }
2274 else
2275 {
2276 /* Now we have all the objects loaded. Relocate them all except for
2277 the dynamic linker itself. We do this in reverse order so that copy
2278 relocs of earlier objects overwrite the data written by later
2279 objects. We do not re-relocate the dynamic linker itself in this
2280 loop because that could result in the GOT entries for functions we
2281 call being changed, and that would break us. It is safe to relocate
2282 the dynamic linker out of order because it has no copy relocs (we
2283 know that because it is self-contained). */
2284
2285 int consider_profiling = GLRO(dl_profile) != NULL;
2286
2287 /* If we are profiling we also must do lazy reloaction. */
2288 GLRO(dl_lazy) |= consider_profiling;
2289
2290 RTLD_TIMING_VAR (start);
2291 rtld_timer_start (&start);
2292 unsigned i = main_map->l_searchlist.r_nlist;
2293 while (i-- > 0)
2294 {
2295 struct link_map *l = main_map->l_initfini[i];
2296
2297 /* While we are at it, help the memory handling a bit. We have to
2298 mark some data structures as allocated with the fake malloc()
2299 implementation in ld.so. */
2300 struct libname_list *lnp = l->l_libname->next;
2301
2302 while (__builtin_expect (lnp != NULL, 0))
2303 {
2304 lnp->dont_free = 1;
2305 lnp = lnp->next;
2306 }
2307 /* Also allocated with the fake malloc(). */
2308 l->l_free_initfini = 0;
2309
2310 if (l != &GL(dl_rtld_map))
2311 _dl_relocate_object (l, l->l_scope, GLRO(dl_lazy) ? RTLD_LAZY : 0,
2312 consider_profiling);
2313
2314 /* Add object to slot information data if necessasy. */
2315 if (l->l_tls_blocksize != 0 && tls_init_tp_called)
2316 _dl_add_to_slotinfo (l, true);
2317 }
2318 rtld_timer_stop (&relocate_time, start);
2319
2320 /* Now enable profiling if needed. Like the previous call,
2321 this has to go here because the calls it makes should use the
2322 rtld versions of the functions (particularly calloc()), but it
2323 needs to have _dl_profile_map set up by the relocator. */
2324 if (__glibc_unlikely (GL(dl_profile_map) != NULL))
2325 /* We must prepare the profiling. */
2326 _dl_start_profile ();
2327 }
2328
2329 if ((!was_tls_init_tp_called && GL(dl_tls_max_dtv_idx) > 0)
2330 || count_modids != _dl_count_modids ())
2331 ++GL(dl_tls_generation);
2332
2333 /* Now that we have completed relocation, the initializer data
2334 for the TLS blocks has its final values and we can copy them
2335 into the main thread's TLS area, which we allocated above.
2336 Note: thread-local variables must only be accessed after completing
2337 the next step. */
2338 _dl_allocate_tls_init (tcbp);
2339
2340 /* And finally install it for the main thread. */
2341 if (! tls_init_tp_called)
2342 {
2343 const char *lossage = TLS_INIT_TP (tcbp);
2344 if (__glibc_unlikely (lossage != NULL))
2345 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
2346 lossage);
2347 }
2348
2349 /* Make sure no new search directories have been added. */
2350 assert (GLRO(dl_init_all_dirs) == GL(dl_all_dirs));
2351
2352 if (! prelinked && rtld_multiple_ref)
2353 {
2354 /* There was an explicit ref to the dynamic linker as a shared lib.
2355 Re-relocate ourselves with user-controlled symbol definitions.
2356
2357 We must do this after TLS initialization in case after this
2358 re-relocation, we might call a user-supplied function
2359 (e.g. calloc from _dl_relocate_object) that uses TLS data. */
2360
2361 /* The malloc implementation has been relocated, so resolving
2362 its symbols (and potentially calling IFUNC resolvers) is safe
2363 at this point. */
2364 __rtld_malloc_init_real (main_map);
2365
2366 RTLD_TIMING_VAR (start);
2367 rtld_timer_start (&start);
2368
2369 /* Mark the link map as not yet relocated again. */
2370 GL(dl_rtld_map).l_relocated = 0;
2371 _dl_relocate_object (&GL(dl_rtld_map), main_map->l_scope, 0, 0);
2372
2373 rtld_timer_accum (&relocate_time, start);
2374 }
2375
2376 /* Relocation is complete. Perform early libc initialization. */
2377 _dl_call_libc_early_init (GL(dl_ns)[LM_ID_BASE].libc_map);
2378
2379 /* Do any necessary cleanups for the startup OS interface code.
2380 We do these now so that no calls are made after rtld re-relocation
2381 which might be resolved to different functions than we expect.
2382 We cannot do this before relocating the other objects because
2383 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
2384 _dl_sysdep_start_cleanup ();
2385
2386 #ifdef SHARED
2387 /* Auditing checkpoint: we have added all objects. */
2388 if (__glibc_unlikely (GLRO(dl_naudit) > 0))
2389 {
2390 struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2391 /* Do not call the functions for any auditing object. */
2392 if (head->l_auditing == 0)
2393 {
2394 struct audit_ifaces *afct = GLRO(dl_audit);
2395 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
2396 {
2397 if (afct->activity != NULL)
2398 afct->activity (&link_map_audit_state (head, cnt)->cookie,
2399 LA_ACT_CONSISTENT);
2400
2401 afct = afct->next;
2402 }
2403 }
2404 }
2405 #endif
2406
2407 /* Notify the debugger all new objects are now ready to go. We must re-get
2408 the address since by now the variable might be in another object. */
2409 r = _dl_debug_initialize (0, LM_ID_BASE);
2410 r->r_state = RT_CONSISTENT;
2411 _dl_debug_state ();
2412 LIBC_PROBE (init_complete, 2, LM_ID_BASE, r);
2413
2414 #if defined USE_LDCONFIG && !defined MAP_COPY
2415 /* We must munmap() the cache file. */
2416 _dl_unload_cache ();
2417 #endif
2418
2419 /* Once we return, _dl_sysdep_start will invoke
2420 the DT_INIT functions and then *USER_ENTRY. */
2421 }
2422 \f
2423 /* This is a little helper function for resolving symbols while
2424 tracing the binary. */
2425 static void
2426 print_unresolved (int errcode __attribute__ ((unused)), const char *objname,
2427 const char *errstring)
2428 {
2429 if (objname[0] == '\0')
2430 objname = RTLD_PROGNAME;
2431 _dl_error_printf ("%s (%s)\n", errstring, objname);
2432 }
2433 \f
2434 /* This is a little helper function for resolving symbols while
2435 tracing the binary. */
2436 static void
2437 print_missing_version (int errcode __attribute__ ((unused)),
2438 const char *objname, const char *errstring)
2439 {
2440 _dl_error_printf ("%s: %s: %s\n", RTLD_PROGNAME,
2441 objname, errstring);
2442 }
2443 \f
2444 /* Nonzero if any of the debugging options is enabled. */
2445 static int any_debug attribute_relro;
2446
2447 /* Process the string given as the parameter which explains which debugging
2448 options are enabled. */
2449 static void
2450 process_dl_debug (const char *dl_debug)
2451 {
2452 /* When adding new entries make sure that the maximal length of a name
2453 is correctly handled in the LD_DEBUG_HELP code below. */
2454 static const struct
2455 {
2456 unsigned char len;
2457 const char name[10];
2458 const char helptext[41];
2459 unsigned short int mask;
2460 } debopts[] =
2461 {
2462 #define LEN_AND_STR(str) sizeof (str) - 1, str
2463 { LEN_AND_STR ("libs"), "display library search paths",
2464 DL_DEBUG_LIBS | DL_DEBUG_IMPCALLS },
2465 { LEN_AND_STR ("reloc"), "display relocation processing",
2466 DL_DEBUG_RELOC | DL_DEBUG_IMPCALLS },
2467 { LEN_AND_STR ("files"), "display progress for input file",
2468 DL_DEBUG_FILES | DL_DEBUG_IMPCALLS },
2469 { LEN_AND_STR ("symbols"), "display symbol table processing",
2470 DL_DEBUG_SYMBOLS | DL_DEBUG_IMPCALLS },
2471 { LEN_AND_STR ("bindings"), "display information about symbol binding",
2472 DL_DEBUG_BINDINGS | DL_DEBUG_IMPCALLS },
2473 { LEN_AND_STR ("versions"), "display version dependencies",
2474 DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS },
2475 { LEN_AND_STR ("scopes"), "display scope information",
2476 DL_DEBUG_SCOPES },
2477 { LEN_AND_STR ("all"), "all previous options combined",
2478 DL_DEBUG_LIBS | DL_DEBUG_RELOC | DL_DEBUG_FILES | DL_DEBUG_SYMBOLS
2479 | DL_DEBUG_BINDINGS | DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS
2480 | DL_DEBUG_SCOPES },
2481 { LEN_AND_STR ("statistics"), "display relocation statistics",
2482 DL_DEBUG_STATISTICS },
2483 { LEN_AND_STR ("unused"), "determined unused DSOs",
2484 DL_DEBUG_UNUSED },
2485 { LEN_AND_STR ("help"), "display this help message and exit",
2486 DL_DEBUG_HELP },
2487 };
2488 #define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
2489
2490 /* Skip separating white spaces and commas. */
2491 while (*dl_debug != '\0')
2492 {
2493 if (*dl_debug != ' ' && *dl_debug != ',' && *dl_debug != ':')
2494 {
2495 size_t cnt;
2496 size_t len = 1;
2497
2498 while (dl_debug[len] != '\0' && dl_debug[len] != ' '
2499 && dl_debug[len] != ',' && dl_debug[len] != ':')
2500 ++len;
2501
2502 for (cnt = 0; cnt < ndebopts; ++cnt)
2503 if (debopts[cnt].len == len
2504 && memcmp (dl_debug, debopts[cnt].name, len) == 0)
2505 {
2506 GLRO(dl_debug_mask) |= debopts[cnt].mask;
2507 any_debug = 1;
2508 break;
2509 }
2510
2511 if (cnt == ndebopts)
2512 {
2513 /* Display a warning and skip everything until next
2514 separator. */
2515 char *copy = strndupa (dl_debug, len);
2516 _dl_error_printf ("\
2517 warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy);
2518 }
2519
2520 dl_debug += len;
2521 continue;
2522 }
2523
2524 ++dl_debug;
2525 }
2526
2527 if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
2528 {
2529 /* In order to get an accurate picture of whether a particular
2530 DT_NEEDED entry is actually used we have to process both
2531 the PLT and non-PLT relocation entries. */
2532 GLRO(dl_lazy) = 0;
2533 }
2534
2535 if (GLRO(dl_debug_mask) & DL_DEBUG_HELP)
2536 {
2537 size_t cnt;
2538
2539 _dl_printf ("\
2540 Valid options for the LD_DEBUG environment variable are:\n\n");
2541
2542 for (cnt = 0; cnt < ndebopts; ++cnt)
2543 _dl_printf (" %.*s%s%s\n", debopts[cnt].len, debopts[cnt].name,
2544 " " + debopts[cnt].len - 3,
2545 debopts[cnt].helptext);
2546
2547 _dl_printf ("\n\
2548 To direct the debugging output into a file instead of standard output\n\
2549 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
2550 _exit (0);
2551 }
2552 }
2553 \f
2554 /* Process all environments variables the dynamic linker must recognize.
2555 Since all of them start with `LD_' we are a bit smarter while finding
2556 all the entries. */
2557 extern char **_environ attribute_hidden;
2558
2559
2560 static void
2561 process_envvars (enum mode *modep, struct audit_list *audit_list)
2562 {
2563 char **runp = _environ;
2564 char *envline;
2565 enum mode mode = normal;
2566 char *debug_output = NULL;
2567
2568 /* This is the default place for profiling data file. */
2569 GLRO(dl_profile_output)
2570 = &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0];
2571
2572 while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
2573 {
2574 size_t len = 0;
2575
2576 while (envline[len] != '\0' && envline[len] != '=')
2577 ++len;
2578
2579 if (envline[len] != '=')
2580 /* This is a "LD_" variable at the end of the string without
2581 a '=' character. Ignore it since otherwise we will access
2582 invalid memory below. */
2583 continue;
2584
2585 switch (len)
2586 {
2587 case 4:
2588 /* Warning level, verbose or not. */
2589 if (memcmp (envline, "WARN", 4) == 0)
2590 GLRO(dl_verbose) = envline[5] != '\0';
2591 break;
2592
2593 case 5:
2594 /* Debugging of the dynamic linker? */
2595 if (memcmp (envline, "DEBUG", 5) == 0)
2596 {
2597 process_dl_debug (&envline[6]);
2598 break;
2599 }
2600 if (memcmp (envline, "AUDIT", 5) == 0)
2601 audit_list_add_string (audit_list, &envline[6]);
2602 break;
2603
2604 case 7:
2605 /* Print information about versions. */
2606 if (memcmp (envline, "VERBOSE", 7) == 0)
2607 {
2608 version_info = envline[8] != '\0';
2609 break;
2610 }
2611
2612 /* List of objects to be preloaded. */
2613 if (memcmp (envline, "PRELOAD", 7) == 0)
2614 {
2615 preloadlist = &envline[8];
2616 break;
2617 }
2618
2619 /* Which shared object shall be profiled. */
2620 if (memcmp (envline, "PROFILE", 7) == 0 && envline[8] != '\0')
2621 GLRO(dl_profile) = &envline[8];
2622 break;
2623
2624 case 8:
2625 /* Do we bind early? */
2626 if (memcmp (envline, "BIND_NOW", 8) == 0)
2627 {
2628 GLRO(dl_lazy) = envline[9] == '\0';
2629 break;
2630 }
2631 if (memcmp (envline, "BIND_NOT", 8) == 0)
2632 GLRO(dl_bind_not) = envline[9] != '\0';
2633 break;
2634
2635 case 9:
2636 /* Test whether we want to see the content of the auxiliary
2637 array passed up from the kernel. */
2638 if (!__libc_enable_secure
2639 && memcmp (envline, "SHOW_AUXV", 9) == 0)
2640 _dl_show_auxv ();
2641 break;
2642
2643 #if !HAVE_TUNABLES
2644 case 10:
2645 /* Mask for the important hardware capabilities. */
2646 if (!__libc_enable_secure
2647 && memcmp (envline, "HWCAP_MASK", 10) == 0)
2648 GLRO(dl_hwcap_mask) = _dl_strtoul (&envline[11], NULL);
2649 break;
2650 #endif
2651
2652 case 11:
2653 /* Path where the binary is found. */
2654 if (!__libc_enable_secure
2655 && memcmp (envline, "ORIGIN_PATH", 11) == 0)
2656 GLRO(dl_origin_path) = &envline[12];
2657 break;
2658
2659 case 12:
2660 /* The library search path. */
2661 if (!__libc_enable_secure
2662 && memcmp (envline, "LIBRARY_PATH", 12) == 0)
2663 {
2664 library_path = &envline[13];
2665 break;
2666 }
2667
2668 /* Where to place the profiling data file. */
2669 if (memcmp (envline, "DEBUG_OUTPUT", 12) == 0)
2670 {
2671 debug_output = &envline[13];
2672 break;
2673 }
2674
2675 if (!__libc_enable_secure
2676 && memcmp (envline, "DYNAMIC_WEAK", 12) == 0)
2677 GLRO(dl_dynamic_weak) = 1;
2678 break;
2679
2680 case 13:
2681 /* We might have some extra environment variable with length 13
2682 to handle. */
2683 #ifdef EXTRA_LD_ENVVARS_13
2684 EXTRA_LD_ENVVARS_13
2685 #endif
2686 if (!__libc_enable_secure
2687 && memcmp (envline, "USE_LOAD_BIAS", 13) == 0)
2688 {
2689 GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0;
2690 break;
2691 }
2692 break;
2693
2694 case 14:
2695 /* Where to place the profiling data file. */
2696 if (!__libc_enable_secure
2697 && memcmp (envline, "PROFILE_OUTPUT", 14) == 0
2698 && envline[15] != '\0')
2699 GLRO(dl_profile_output) = &envline[15];
2700 break;
2701
2702 case 16:
2703 /* The mode of the dynamic linker can be set. */
2704 if (memcmp (envline, "TRACE_PRELINKING", 16) == 0)
2705 {
2706 mode = trace;
2707 GLRO(dl_verbose) = 1;
2708 GLRO(dl_debug_mask) |= DL_DEBUG_PRELINK;
2709 GLRO(dl_trace_prelink) = &envline[17];
2710 }
2711 break;
2712
2713 case 20:
2714 /* The mode of the dynamic linker can be set. */
2715 if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0)
2716 mode = trace;
2717 break;
2718
2719 /* We might have some extra environment variable to handle. This
2720 is tricky due to the pre-processing of the length of the name
2721 in the switch statement here. The code here assumes that added
2722 environment variables have a different length. */
2723 #ifdef EXTRA_LD_ENVVARS
2724 EXTRA_LD_ENVVARS
2725 #endif
2726 }
2727 }
2728
2729 /* The caller wants this information. */
2730 *modep = mode;
2731
2732 /* Extra security for SUID binaries. Remove all dangerous environment
2733 variables. */
2734 if (__builtin_expect (__libc_enable_secure, 0))
2735 {
2736 static const char unsecure_envvars[] =
2737 #ifdef EXTRA_UNSECURE_ENVVARS
2738 EXTRA_UNSECURE_ENVVARS
2739 #endif
2740 UNSECURE_ENVVARS;
2741 const char *nextp;
2742
2743 nextp = unsecure_envvars;
2744 do
2745 {
2746 unsetenv (nextp);
2747 /* We could use rawmemchr but this need not be fast. */
2748 nextp = (char *) (strchr) (nextp, '\0') + 1;
2749 }
2750 while (*nextp != '\0');
2751
2752 if (__access ("/etc/suid-debug", F_OK) != 0)
2753 {
2754 #if !HAVE_TUNABLES
2755 unsetenv ("MALLOC_CHECK_");
2756 #endif
2757 GLRO(dl_debug_mask) = 0;
2758 }
2759
2760 if (mode != normal)
2761 _exit (5);
2762 }
2763 /* If we have to run the dynamic linker in debugging mode and the
2764 LD_DEBUG_OUTPUT environment variable is given, we write the debug
2765 messages to this file. */
2766 else if (any_debug && debug_output != NULL)
2767 {
2768 const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW;
2769 size_t name_len = strlen (debug_output);
2770 char buf[name_len + 12];
2771 char *startp;
2772
2773 buf[name_len + 11] = '\0';
2774 startp = _itoa (__getpid (), &buf[name_len + 11], 10, 0);
2775 *--startp = '.';
2776 startp = memcpy (startp - name_len, debug_output, name_len);
2777
2778 GLRO(dl_debug_fd) = __open64_nocancel (startp, flags, DEFFILEMODE);
2779 if (GLRO(dl_debug_fd) == -1)
2780 /* We use standard output if opening the file failed. */
2781 GLRO(dl_debug_fd) = STDOUT_FILENO;
2782 }
2783 }
2784
2785 #if HP_TIMING_INLINE
2786 static void
2787 print_statistics_item (const char *title, hp_timing_t time,
2788 hp_timing_t total)
2789 {
2790 char cycles[HP_TIMING_PRINT_SIZE];
2791 HP_TIMING_PRINT (cycles, sizeof (cycles), time);
2792
2793 char relative[3 * sizeof (hp_timing_t) + 2];
2794 char *cp = _itoa ((1000ULL * time) / total, relative + sizeof (relative),
2795 10, 0);
2796 /* Sets the decimal point. */
2797 char *wp = relative;
2798 switch (relative + sizeof (relative) - cp)
2799 {
2800 case 3:
2801 *wp++ = *cp++;
2802 /* Fall through. */
2803 case 2:
2804 *wp++ = *cp++;
2805 /* Fall through. */
2806 case 1:
2807 *wp++ = '.';
2808 *wp++ = *cp++;
2809 }
2810 *wp = '\0';
2811 _dl_debug_printf ("%s: %s cycles (%s%%)\n", title, cycles, relative);
2812 }
2813 #endif
2814
2815 /* Print the various times we collected. */
2816 static void
2817 __attribute ((noinline))
2818 print_statistics (const hp_timing_t *rtld_total_timep)
2819 {
2820 #if HP_TIMING_INLINE
2821 {
2822 char cycles[HP_TIMING_PRINT_SIZE];
2823 HP_TIMING_PRINT (cycles, sizeof (cycles), *rtld_total_timep);
2824 _dl_debug_printf ("\nruntime linker statistics:\n"
2825 " total startup time in dynamic loader: %s cycles\n",
2826 cycles);
2827 print_statistics_item (" time needed for relocation",
2828 relocate_time, *rtld_total_timep);
2829 }
2830 #endif
2831
2832 unsigned long int num_relative_relocations = 0;
2833 for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns)
2834 {
2835 if (GL(dl_ns)[ns]._ns_loaded == NULL)
2836 continue;
2837
2838 struct r_scope_elem *scope = &GL(dl_ns)[ns]._ns_loaded->l_searchlist;
2839
2840 for (unsigned int i = 0; i < scope->r_nlist; i++)
2841 {
2842 struct link_map *l = scope->r_list [i];
2843
2844 if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELCOUNT)])
2845 num_relative_relocations
2846 += l->l_info[VERSYMIDX (DT_RELCOUNT)]->d_un.d_val;
2847 #ifndef ELF_MACHINE_REL_RELATIVE
2848 /* Relative relocations are processed on these architectures if
2849 library is loaded to different address than p_vaddr or
2850 if not prelinked. */
2851 if ((l->l_addr != 0 || !l->l_info[VALIDX(DT_GNU_PRELINKED)])
2852 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
2853 #else
2854 /* On e.g. IA-64 or Alpha, relative relocations are processed
2855 only if library is loaded to different address than p_vaddr. */
2856 if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
2857 #endif
2858 num_relative_relocations
2859 += l->l_info[VERSYMIDX (DT_RELACOUNT)]->d_un.d_val;
2860 }
2861 }
2862
2863 _dl_debug_printf (" number of relocations: %lu\n"
2864 " number of relocations from cache: %lu\n"
2865 " number of relative relocations: %lu\n",
2866 GL(dl_num_relocations),
2867 GL(dl_num_cache_relocations),
2868 num_relative_relocations);
2869
2870 #if HP_TIMING_INLINE
2871 print_statistics_item (" time needed to load objects",
2872 load_time, *rtld_total_timep);
2873 #endif
2874 }
This page took 0.174682 seconds and 5 git commands to generate.