summary refs log tree commit diff
path: root/elf/rtld.c
blob: 726463c882d33df58ffac70604eb89ba5e30b7fa (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
/* Run time dynamic linker.
   Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <link.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>		/* Check if MAP_ANON is defined.  */
#include <stdio-common/_itoa.h>
#include <assert.h>
#include <entry.h>
#include "dynamic-link.h"


/* System-specific function to do initial startup for the dynamic linker.
   After this, file access calls and getenv must work.  This is responsible
   for setting __libc_enable_secure if we need to be secure (e.g. setuid),
   and for setting _dl_argc and _dl_argv, and then calling _dl_main.  */
extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
				    void (*dl_main) (const ElfW(Phdr) *phdr,
						     ElfW(Half) phent,
						     ElfW(Addr) *user_entry));
extern void _dl_sysdep_start_cleanup (void);

/* System-dependent function to read a file's whole contents
   in the most convenient manner available.  */
extern void *_dl_sysdep_read_whole_file (const char *filename,
					 size_t *filesize_ptr,
					 int mmap_prot);

/* Helper function to handle errors while resolving symbols.  */
static void print_unresolved (int errcode, const char *objname,
			      const char *errsting);

/* Helper function to handle errors when a version is missing.  */
static void print_missing_version (int errcode, const char *objname,
				   const char *errsting);


int _dl_argc;
char **_dl_argv;
const char *_dl_rpath;
int _dl_verbose;
const char *_dl_platform;
size_t _dl_platformlen;
struct r_search_path *_dl_search_paths;
const char *_dl_profile;
const char *_dl_profile_output;
struct link_map *_dl_profile_map;

/* Set nonzero during loading and initialization of executable and
   libraries, cleared before the executable's entry point runs.  This
   must not be initialized to nonzero, because the unused dynamic
   linker loaded in for libc.so's "ld.so.1" dep will provide the
   definition seen by libc.so's initializer; that value must be zero,
   and will be since that dynamic linker's _dl_start and dl_main will
   never be called.  */
int _dl_starting_up;

static void dl_main (const ElfW(Phdr) *phdr,
		     ElfW(Half) phent,
		     ElfW(Addr) *user_entry);

struct link_map _dl_rtld_map;
struct libname_list _dl_rtld_libname;

#ifdef RTLD_START
RTLD_START
#else
#error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
#endif

static ElfW(Addr)
_dl_start (void *arg)
{
  struct link_map bootstrap_map;

  /* This #define produces dynamic linking inline functions for
     bootstrap relocation instead of general-purpose relocation.  */
#define RTLD_BOOTSTRAP
#define RESOLVE(sym, version, flags) bootstrap_map.l_addr
#include "dynamic-link.h"

  /* Figure out the run-time load address of the dynamic linker itself.  */
  bootstrap_map.l_addr = elf_machine_load_address ();

  /* Read our own dynamic section and fill in the info array.  */
  bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
  elf_get_dynamic_info (bootstrap_map.l_ld, bootstrap_map.l_info);

#ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
  ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info);
#endif

  /* Relocate ourselves so we can do normal function calls and
     data access using the global offset table.  */

  ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, 0);

  /* Now life is sane; we can call functions and access global data.
     Set up to use the operating system facilities, and find out from
     the operating system's program loader where to find the program
     header table in core.  */


  /* Transfer data about ourselves to the permanent link_map structure.  */
  _dl_rtld_map.l_addr = bootstrap_map.l_addr;
  _dl_rtld_map.l_ld = bootstrap_map.l_ld;
  memcpy (_dl_rtld_map.l_info, bootstrap_map.l_info,
	  sizeof _dl_rtld_map.l_info);
  _dl_setup_hash (&_dl_rtld_map);

  /* Cache the DT_RPATH stored in ld.so itself; this will be
     the default search path.  */
  _dl_rpath = (void *) (_dl_rtld_map.l_addr +
			_dl_rtld_map.l_info[DT_STRTAB]->d_un.d_ptr +
			_dl_rtld_map.l_info[DT_RPATH]->d_un.d_val);

  /* Call the OS-dependent function to set up life so we can do things like
     file access.  It will call `dl_main' (below) to do all the real work
     of the dynamic linker, and then unwind our frame and run the user
     entry point on the same stack we entered on.  */
  return _dl_sysdep_start (arg, &dl_main);
}


/* Now life is peachy; we can do all normal operations.
   On to the real work.  */

void ENTRY_POINT (void);

/* Some helper functions.  */

/* Arguments to relocate_doit.  */
struct relocate_args
{
  struct link_map *l;
  int lazy;
};

struct map_args
{
  /* Argument to map_doit.  */
  char *str;
  /* Return value of map_doit.  */
  struct link_map *main_map;
};

/* Arguments to version_check_doit.  */
struct version_check_args
{
  struct link_map *main_map;
  int doexit;
};

static void
relocate_doit (void *a)
{
  struct relocate_args *args = (struct relocate_args *) a;

  _dl_relocate_object (args->l, _dl_object_relocation_scope (args->l),
		       args->lazy);
}

static void
map_doit (void *a)
{
  struct map_args *args = (struct map_args *)a;
  args->main_map = _dl_map_object (NULL, args->str, lt_library, 0);
}

static void
version_check_doit (void *a)
{
  struct version_check_args *args = (struct version_check_args *)a;
  if (_dl_check_all_versions (args->main_map, 1) && args->doexit)
    /* We cannot start the application.  Abort now.  */
    _exit (1);
}


static inline struct link_map *
find_needed (const char *name)
{
  unsigned int n;

  for (n = 0; n < _dl_loaded->l_nsearchlist; ++n)
    if (_dl_name_match_p (name, _dl_loaded->l_searchlist[n]))
      return _dl_loaded->l_searchlist[n];

  /* Should never happen.  */
  return NULL;
}

static int
match_version (const char *string, struct link_map *map)
{
  const char *strtab = (const char *) (map->l_addr
				       + map->l_info[DT_STRTAB]->d_un.d_ptr);
  ElfW(Verdef) *def;

#define VERDEFTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
  if (map->l_info[VERDEFTAG] == NULL)
    /* The file has no symbol versioning.  */
    return 0;

  def = (ElfW(Verdef) *) ((char *) map->l_addr
			  + map->l_info[VERDEFTAG]->d_un.d_ptr);
  while (1)
    {
      ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);

      /* Compare the version strings.  */
      if (strcmp (string, strtab + aux->vda_name) == 0)
	/* Bingo!  */
	return 1;

      /* If no more definitions we failed to find what we want.  */
      if (def->vd_next == 0)
	break;

      /* Next definition.  */
      def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
    }

  return 0;
}

unsigned int _dl_skip_args;	/* Nonzero if we were run directly.  */

static void
dl_main (const ElfW(Phdr) *phdr,
	 ElfW(Half) phent,
	 ElfW(Addr) *user_entry)
{
  const ElfW(Phdr) *ph;
  struct link_map *main_map;
  int lazy;
  enum { normal, list, verify, trace } mode;
  struct link_map **preloads;
  unsigned int npreloads;
  const char *preloadlist;
  size_t file_size;
  char *file;
  int has_interp = 0;

  mode = getenv ("LD_TRACE_LOADED_OBJECTS") != NULL ? trace : normal;
  _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;

  /* LAZY is determined by the environment variable LD_WARN and
     LD_BIND_NOW if we trace the binary.  */
  if (mode == trace)
    lazy = (_dl_verbose
	    ? (*(getenv ("LD_BIND_NOW") ?: "") == '\0' ? 1 : 0) : -1);
  else
    lazy = !__libc_enable_secure && *(getenv ("LD_BIND_NOW") ?: "") == '\0';

  /* See whether we want to use profiling.  */
  _dl_profile = getenv ("LD_PROFILE");
  if (_dl_profile != NULL)
    if (_dl_profile[0] == '\0')
      /* An empty string is of not much help.  Disable profiling.  */
      _dl_profile = NULL;
    else
      {
	/* OK, we have the name of a shared object we want to
	   profile.  It's up to the user to provide a good name, it
	   must match the file name or soname of one of the loaded
	   objects.  Now let's see where we are supposed to place the
	   result.  */
	_dl_profile_output = getenv ("LD_PROFILE_OUTPUT");

	if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0')
	  /* This is the default place.  */
	  _dl_profile_output = "/var/tmp";
      }

  /* Set up a flag which tells we are just starting.  */
  _dl_starting_up = 1;

  if (*user_entry == (ElfW(Addr)) &ENTRY_POINT)
    {
      /* Ho ho.  We are not the program interpreter!  We are the program
	 itself!  This means someone ran ld.so as a command.  Well, that
	 might be convenient to do sometimes.  We support it by
	 interpreting the args like this:

	 ld.so PROGRAM ARGS...

	 The first argument is the name of a file containing an ELF
	 executable we will load and run with the following arguments.
	 To simplify life here, PROGRAM is searched for using the
	 normal rules for shared objects, rather than $PATH or anything
	 like that.  We just load it and use its entry point; we don't
	 pay attention to its PT_INTERP command (we are the interpreter
	 ourselves).  This is an easy way to test a new ld.so before
	 installing it.  */
      if (_dl_argc < 2)
	_dl_sysdep_fatal ("\
Usage: ld.so [--list|--verify] EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
You have invoked `ld.so', the helper program for shared library executables.\n\
This program usually lives in the file `/lib/ld.so', and special directives\n\
in executable files using ELF shared libraries tell the system's program\n\
loader to load the helper program from this file.  This helper program loads\n\
the shared libraries needed by the program executable, prepares the program\n\
to run, and runs it.  You may invoke this helper program directly from the\n\
command line to load and run an ELF executable file; this is like executing\n\
that file itself, but always uses this helper program from the file you\n\
specified, instead of the helper program file specified in the executable\n\
file you run.  This is mostly of use for maintainers to test new versions\n\
of this helper program; chances are you did not intend to run this program.\n",
			  NULL);

      /* Note the place where the dynamic linker actually came from.  */
      _dl_rtld_map.l_name = _dl_argv[0];

      while (_dl_argc > 1)
	if (! strcmp (_dl_argv[1], "--list"))
	  {
	    mode = list;
	    lazy = -1;	/* This means do no dependency analysis.  */

	    ++_dl_skip_args;
	    --_dl_argc;
	    ++_dl_argv;
	  }
	else if (! strcmp (_dl_argv[1], "--verify"))
	  {
	    mode = verify;

	    ++_dl_skip_args;
	    --_dl_argc;
	    ++_dl_argv;
	  }
	else
	  break;

      ++_dl_skip_args;
      --_dl_argc;
      ++_dl_argv;

      if (mode == verify)
	{
	  char *err_str = NULL;
	  const char *obj_name __attribute__ ((unused));
	  struct map_args args;

	  args.str = _dl_argv[0];
	  (void) _dl_catch_error (&err_str, &obj_name, map_doit, &args);
	  main_map = args.main_map;
	  if (err_str != NULL)
	    {
	      free (err_str);
	      _exit (EXIT_FAILURE);
	    }
	}
      else
	main_map = _dl_map_object (NULL, _dl_argv[0], lt_library, 0);

      phdr = main_map->l_phdr;
      phent = main_map->l_phnum;
      main_map->l_name = (char *) "";
      *user_entry = main_map->l_entry;
    }
  else
    {
      /* Create a link_map for the executable itself.
	 This will be what dlopen on "" returns.  */
      main_map = _dl_new_object ((char *) "", "", lt_executable);
      if (main_map == NULL)
	_dl_sysdep_fatal ("cannot allocate memory for link map\n", NULL);
      main_map->l_phdr = phdr;
      main_map->l_phnum = phent;
      main_map->l_entry = *user_entry;
      main_map->l_opencount = 1;
    }

  /* Scan the program header table for the dynamic section.  */
  for (ph = phdr; ph < &phdr[phent]; ++ph)
    switch (ph->p_type)
      {
      case PT_DYNAMIC:
	/* This tells us where to find the dynamic section,
	   which tells us everything we need to do.  */
	main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
	break;
      case PT_INTERP:
	/* This "interpreter segment" was used by the program loader to
	   find the program interpreter, which is this program itself, the
	   dynamic linker.  We note what name finds us, so that a future
	   dlopen call or DT_NEEDED entry, for something that wants to link
	   against the dynamic linker as a shared library, will know that
	   the shared object is already loaded.  */
	_dl_rtld_libname.name = (const char *) main_map->l_addr + ph->p_vaddr;
	_dl_rtld_libname.next = NULL;
	_dl_rtld_map.l_libname = &_dl_rtld_libname;
	has_interp = 1;
	break;
      }
  if (! _dl_rtld_map.l_libname && _dl_rtld_map.l_name)
    {
      /* We were invoked directly, so the program might not have a
	 PT_INTERP.  */
      _dl_rtld_libname.name = _dl_rtld_map.l_name;
      _dl_rtld_libname.next = NULL;
      _dl_rtld_map.l_libname =  &_dl_rtld_libname;
    }
  else
    assert (_dl_rtld_map.l_libname); /* How else did we get here?  */

  if (mode == verify)
    /* We were called just to verify that this is a dynamic executable
       using us as the program interpreter.  */
    _exit (main_map->l_ld == NULL ? 1 : has_interp ? 0 : 2);

  /* Extract the contents of the dynamic section for easy access.  */
  elf_get_dynamic_info (main_map->l_ld, main_map->l_info);
  if (main_map->l_info[DT_HASH])
    /* Set up our cache of pointers into the hash table.  */
    _dl_setup_hash (main_map);

  /* Put the link_map for ourselves on the chain so it can be found by
     name.  Note that at this point the global chain of link maps contains
     exactly one element, which is pointed to by main_map.  */
  if (! _dl_rtld_map.l_name)
    /* If not invoked directly, the dynamic linker shared object file was
       found by the PT_INTERP name.  */
    _dl_rtld_map.l_name = (char *) _dl_rtld_map.l_libname->name;
  _dl_rtld_map.l_type = lt_library;
  main_map->l_next = &_dl_rtld_map;
  _dl_rtld_map.l_prev = main_map;

  /* We have two ways to specify objects to preload: via environment
     variable and via the file /etc/ld.so.preload.  The later can also
     be used when security is enabled.  */
  preloads = NULL;
  npreloads = 0;

  preloadlist = getenv ("LD_PRELOAD");
  if (preloadlist)
    {
      /* The LD_PRELOAD environment variable gives a white space
	 separated list of libraries that are loaded before the
	 executable's dependencies and prepended to the global scope
	 list.  If the binary is running setuid all elements
	 containing a '/' are ignored since it is insecure.  */
      char *list = strdupa (preloadlist);
      char *p;
      while ((p = strsep (&list, " ")) != NULL)
	if (! __libc_enable_secure || strchr (p, '/') == NULL)
	  {
	    (void) _dl_map_object (NULL, p, lt_library, 0);
	    ++npreloads;
	  }
    }

  /* Read the contents of the file.  */
  file = _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size,
				     PROT_READ | PROT_WRITE);
  if (file)
    {
      /* Parse the file.  It contains names of libraries to be loaded,
	 separated by white spaces or `:'.  It may also contain
	 comments introduced by `#'.  */
      char *problem;
      char *runp;
      size_t rest;

      /* Eliminate comments.  */
      runp = file;
      rest = file_size;
      while (rest > 0)
	{
	  char *comment = memchr (runp, '#', rest);
	  if (comment == NULL)
	    break;

	  rest -= comment - runp;
	  do
	    *comment = ' ';
	  while (--rest > 0 && *++comment != '\n');
	}

      /* We have one problematic case: if we have a name at the end of
	 the file without a trailing terminating characters, we cannot
	 place the \0.  Handle the case separately.  */
      if (file[file_size - 1] != ' ' && file[file_size] != '\t'
	  && file[file_size] != '\n')
	{
	  problem = &file[file_size];
	  while (problem > file && problem[-1] != ' ' && problem[-1] != '\t'
		 && problem[-1] != '\n')
	    --problem;

	  if (problem > file)
	    problem[-1] = '\0';
	}
      else
	problem = NULL;

      if (file != problem)
	{
	  char *p;
	  runp = file;
	  while ((p = strsep (&runp, ": \t\n")) != NULL)
	    {
	      (void) _dl_map_object (NULL, p, lt_library, 0);
	      ++npreloads;
	    }
	}

      if (problem != NULL)
	{
	  char *p = strndupa (problem, file_size - (problem - file));
	  (void) _dl_map_object (NULL, p, lt_library, 0);
	}

      /* We don't need the file anymore.  */
      __munmap (file, file_size);
    }

  if (npreloads != 0)
    {
      /* Set up PRELOADS with a vector of the preloaded libraries.  */
      struct link_map *l;
      unsigned int i;
      preloads = __alloca (npreloads * sizeof preloads[0]);
      l = _dl_rtld_map.l_next; /* End of the chain before preloads.  */
      i = 0;
      do
	{
	  preloads[i++] = l;
	  l = l->l_next;
	} while (l);
      assert (i == npreloads);
    }

  /* Initialize the data structures for the search paths for shared
     objects.  */
  _dl_init_paths ();

  /* Load all the libraries specified by DT_NEEDED entries.  If LD_PRELOAD
     specified some libraries to load, these are inserted before the actual
     dependencies in the executable's searchlist for symbol resolution.  */
  _dl_map_object_deps (main_map, preloads, npreloads, mode == trace);

#ifndef MAP_ANON
  /* We are done mapping things, so close the zero-fill descriptor.  */
  __close (_dl_zerofd);
  _dl_zerofd = -1;
#endif

  /* Remove _dl_rtld_map from the chain.  */
  _dl_rtld_map.l_prev->l_next = _dl_rtld_map.l_next;
  if (_dl_rtld_map.l_next)
    _dl_rtld_map.l_next->l_prev = _dl_rtld_map.l_prev;

  if (_dl_rtld_map.l_opencount)
    {
      /* Some DT_NEEDED entry referred to the interpreter object itself, so
	 put it back in the list of visible objects.  We insert it into the
	 chain in symbol search order because gdb uses the chain's order as
	 its symbol search order.  */
      unsigned int i = 1;
      while (main_map->l_searchlist[i] != &_dl_rtld_map)
	++i;
      _dl_rtld_map.l_prev = main_map->l_searchlist[i - 1];
      _dl_rtld_map.l_next = (i + 1 < main_map->l_nsearchlist ?
			     main_map->l_searchlist[i + 1] : NULL);
      assert (_dl_rtld_map.l_prev->l_next == _dl_rtld_map.l_next);
      _dl_rtld_map.l_prev->l_next = &_dl_rtld_map;
      if (_dl_rtld_map.l_next)
	{
	  assert (_dl_rtld_map.l_next->l_prev == _dl_rtld_map.l_prev);
	  _dl_rtld_map.l_next->l_prev = &_dl_rtld_map;
	}
    }

  /* Now let us see whether all libraries are available in the
     versions we need.  */
  {
    struct version_check_args args;
    args.doexit = mode == normal;
    args.main_map = main_map;
    _dl_receive_error (print_missing_version, version_check_doit, &args);
  }

  if (mode != normal)
    {
      /* We were run just to list the shared libraries.  It is
	 important that we do this before real relocation, because the
	 functions we call below for output may no longer work properly
	 after relocation.  */

      int i;

      if (! _dl_loaded->l_info[DT_NEEDED])
	_dl_sysdep_message ("\t", "statically linked\n", NULL);
      else
	{
	  struct link_map *l;

	  for (l = _dl_loaded->l_next; l; l = l->l_next)
	    if (l->l_opencount == 0)
	      /* The library was not found.  */
	      _dl_sysdep_message ("\t", l->l_libname->name, " => not found\n",
				  NULL);
	    else
	      {
		char buf[20], *bp;
		buf[sizeof buf - 1] = '\0';
		bp = _itoa (l->l_addr, &buf[sizeof buf - 1], 16, 0);
		while ((size_t) (&buf[sizeof buf - 1] - bp)
		       < sizeof l->l_addr * 2)
		  *--bp = '0';
		_dl_sysdep_message ("\t", l->l_libname->name, " => ",
				    l->l_name, " (0x", bp, ")\n", NULL);
	      }
	}

      if (mode != trace)
	for (i = 1; i < _dl_argc; ++i)
	  {
	    const ElfW(Sym) *ref = NULL;
	    ElfW(Addr) loadbase = _dl_lookup_symbol (_dl_argv[i], &ref,
						     &_dl_default_scope[2],
						     "argument",
						     ELF_MACHINE_RELOC_NOPLT);
	    char buf[20], *bp;
	    buf[sizeof buf - 1] = '\0';
	    bp = _itoa (ref->st_value, &buf[sizeof buf - 1], 16, 0);
	    while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof loadbase * 2)
	      *--bp = '0';
	    _dl_sysdep_message (_dl_argv[i], " found at 0x", bp, NULL);
	    buf[sizeof buf - 1] = '\0';
	    bp = _itoa (loadbase, &buf[sizeof buf - 1], 16, 0);
	    while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof loadbase * 2)
	      *--bp = '0';
	    _dl_sysdep_message (" in object at 0x", bp, "\n", NULL);
	  }
      else
	{
	  if (lazy >= 0)
	    {
	      /* We have to do symbol dependency testing.  */
	      struct relocate_args args;
	      struct link_map *l;

	      args.lazy = lazy;

	      l = _dl_loaded;
	      while (l->l_next)
		l = l->l_next;
	      do
		{
		  if (l != &_dl_rtld_map && l->l_opencount > 0)
		    {
		      args.l = l;
		      _dl_receive_error (print_unresolved, relocate_doit,
					 &args);
		      *_dl_global_scope_end = NULL;
		    }
		  l = l->l_prev;
		} while (l);
	    }

#define VERNEEDTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
	  if (*(getenv ("LD_VERBOSE") ?: "") != '\0')
	    {
	      /* Print more information.  This means here, print information
		 about the versions needed.  */
	      int first = 1;
	      struct link_map *map = _dl_loaded;

	      for (map = _dl_loaded; map != NULL; map = map->l_next)
		{
		  const char *strtab =
		    (const char *) (map->l_addr
				    + map->l_info[DT_STRTAB]->d_un.d_ptr);
		  ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG];

		  if (dyn != NULL)
		    {
		      ElfW(Verneed) *ent =
			(ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);

		      if (first)
			{
			  _dl_sysdep_message ("\n\tVersion information:\n",
					      NULL);
			  first = 0;
			}

		      _dl_sysdep_message ("\t", (map->l_name[0]
						 ? map->l_name
						 : _dl_argv[0]), ":\n",
					  NULL);

		      while (1)
			{
			  ElfW(Vernaux) *aux;
			  struct link_map *needed;

			  needed = find_needed (strtab + ent->vn_file);
			  aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);

			  while (1)
			    {
			      const char *fname = NULL;

			      _dl_sysdep_message ("\t\t",
						  strtab + ent->vn_file,
						  " (", strtab + aux->vna_name,
						  ") ",
						  (aux->vna_flags
						   & VER_FLG_WEAK
						   ? "[WEAK] " : ""),
						  "=> ", NULL);

			      if (needed != NULL
				  && match_version (strtab + aux->vna_name,
						    needed))
				fname = needed->l_name;

			      _dl_sysdep_message (fname ?: "not found", "\n",
						  NULL);

			      if (aux->vna_next == 0)
				/* No more symbols.  */
				break;

			      /* Next symbol.  */
			      aux = (ElfW(Vernaux) *) ((char *) aux
						   + aux->vna_next);
			    }

			  if (ent->vn_next == 0)
			    /* No more dependencies.  */
			    break;

			  /* Next dependency.  */
			  ent = (ElfW(Verneed) *) ((char *) ent
						   + ent->vn_next);
			}
		    }
		}
	    }
	}

      _exit (0);
    }

  {
    /* Now we have all the objects loaded.  Relocate them all except for
       the dynamic linker itself.  We do this in reverse order so that copy
       relocs of earlier objects overwrite the data written by later
       objects.  We do not re-relocate the dynamic linker itself in this
       loop because that could result in the GOT entries for functions we
       call being changed, and that would break us.  It is safe to relocate
       the dynamic linker out of order because it has no copy relocs (we
       know that because it is self-contained).  */

    struct link_map *l;
    l = _dl_loaded;
    while (l->l_next)
      l = l->l_next;
    do
      {
	if (l != &_dl_rtld_map)
	  {
	    _dl_relocate_object (l, _dl_object_relocation_scope (l), lazy);
	    *_dl_global_scope_end = NULL;
	  }
	l = l->l_prev;
      } while (l);

    /* Do any necessary cleanups for the startup OS interface code.
       We do these now so that no calls are made after rtld re-relocation
       which might be resolved to different functions than we expect.
       We cannot do this before relocating the other objects because
       _dl_relocate_object might need to call `mprotect' for DT_TEXTREL.  */
    _dl_sysdep_start_cleanup ();

    if (_dl_rtld_map.l_opencount > 0)
      /* There was an explicit ref to the dynamic linker as a shared lib.
	 Re-relocate ourselves with user-controlled symbol definitions.  */
      _dl_relocate_object (&_dl_rtld_map, &_dl_default_scope[2], 0);
  }

  {
    /* Initialize _r_debug.  */
    struct r_debug *r = _dl_debug_initialize (_dl_rtld_map.l_addr);
    struct link_map *l;

    l = _dl_loaded;

#ifdef ELF_MACHINE_DEBUG_SETUP

    /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way.  */

    ELF_MACHINE_DEBUG_SETUP (l, r);
    ELF_MACHINE_DEBUG_SETUP (&_dl_rtld_map, r);

#else

    if (l->l_info[DT_DEBUG])
      /* There is a DT_DEBUG entry in the dynamic section.  Fill it in
	 with the run-time address of the r_debug structure  */
      l->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;

    /* Fill in the pointer in the dynamic linker's own dynamic section, in
       case you run gdb on the dynamic linker directly.  */
    if (_dl_rtld_map.l_info[DT_DEBUG])
      _dl_rtld_map.l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;

#endif

    /* Notify the debugger that all objects are now mapped in.  */
    r->r_state = RT_ADD;
    _dl_debug_state ();
  }

  /* Now enable profiling if needed.  */
  if (_dl_profile_map != NULL)
    /* We must prepare the profiling.  */
    _dl_start_profile (_dl_profile_map, _dl_profile_output);

  /* Once we return, _dl_sysdep_start will invoke
     the DT_INIT functions and then *USER_ENTRY.  */
}

/* This is a little helper function for resolving symbols while
   tracing the binary.  */
static void
print_unresolved (int errcode __attribute__ ((unused)), const char *objname,
		  const char *errstring)
{
  if (objname[0] == '\0')
    objname = _dl_argv[0] ?: "<main program>";
  _dl_sysdep_error (errstring, "	(", objname, ")\n", NULL);
}

/* This is a little helper function for resolving symbols while
   tracing the binary.  */
static void
print_missing_version (int errcode __attribute__ ((unused)),
		       const char *objname, const char *errstring)
{
  _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", ": ",
		    objname, ": ", errstring, "\n", NULL);
}