summaryrefslogtreecommitdiff
path: root/elf/rtld.c
blob: 064cd20dd3ca86665a8454e72c386647af5a67d4 (plain)
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
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
/* Run time dynamic linker.
   Copyright (C) 1995, 1996, 1997, 1998, 1999 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 <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>		/* Check if MAP_ANON is defined.  */
#include <elf/ldsodefs.h>
#include <stdio-common/_itoa.h>
#include <entry.h>
#include <fpu_control.h>
#include <hp-timing.h>
#include "dynamic-link.h"
#include "dl-librecon.h"

#include <assert.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);

/* This function is used to unload the cache file if necessary.  */
extern void _dl_unload_cache (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);

/* Print the various times we collected.  */
static void print_statistics (void);

/* This is a list of all the modes the dynamic loader can be in.  */
enum mode { normal, list, verify, trace };

/* Process all environments variables the dynamic linker must recognize.
   Since all of them start with `LD_' we are a bit smarter while finding
   all the entries.  */
static void process_envvars (enum mode *modep, int *lazyp);

int _dl_argc;
char **_dl_argv;
unsigned int _dl_skip_args;	/* Nonzero if we were run directly.  */
int _dl_verbose;
const char *_dl_platform;
size_t _dl_platformlen;
unsigned long _dl_hwcap;
fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
struct r_search_path *_dl_search_paths;
const char *_dl_profile;
const char *_dl_profile_output;
struct link_map *_dl_profile_map;
int _dl_lazy;
int _dl_debug_libs;
int _dl_debug_impcalls;
int _dl_debug_bindings;
int _dl_debug_symbols;
int _dl_debug_versions;
int _dl_debug_reloc;
int _dl_debug_files;
int _dl_debug_statistics;
const char *_dl_inhibit_rpath;		/* RPATH values which should be
					   ignored.  */
const char *_dl_origin_path;

/* This is a pointer to the map for the main object and through it to
   all loaded objects.  */
struct link_map *_dl_loaded;
/* Pointer to the l_searchlist element of the link map of the main object.  */
struct r_scope_elem *_dl_main_searchlist;
/* Copy of the content of `_dl_main_searchlist'.  */
struct r_scope_elem _dl_initial_searchlist;
/* Array which is used when looking up in the global scope.  */
struct r_scope_elem *_dl_global_scope[2];

/* 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;
struct libname_list _dl_rtld_libname2;

/* Variable for statistics.  */
static hp_timing_t rtld_total_time;
static hp_timing_t relocate_time;
static hp_timing_t load_time;
extern unsigned long int _dl_num_relocations;	/* in dl-lookup.c */

#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;
  hp_timing_t start_time;
  ElfW(Addr) start_addr;

  /* This #define produces dynamic linking inline functions for
     bootstrap relocation instead of general-purpose relocation.  */
#define RTLD_BOOTSTRAP
#define RESOLVE(sym, version, flags) \
  ((*(sym))->st_shndx == SHN_UNDEF ? 0 : bootstrap_map.l_addr)
#include "dynamic-link.h"

  if (HP_TIMING_INLINE && HP_TIMING_AVAIL)
    HP_TIMING_NOW (start_time);

  /* 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_addr,
			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);
  /* Please note that we don't allow profiling of this object and
     therefore need not test whether we have to allocate the array
     for the relocation results (as done in dl-reloc.c).  */

  /* 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.  */

  if (HP_TIMING_AVAIL)
    {
      /* If it hasn't happen yet record the startup time.  */
      if (! HP_TIMING_INLINE)
	HP_TIMING_NOW (start_time);

      /* Initialize the timing functions.  */
      HP_TIMING_DIFF_INIT ();
    }

  /* 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;
  _dl_rtld_map.l_opencount = 1;
  memcpy (_dl_rtld_map.l_info, bootstrap_map.l_info,
	  sizeof _dl_rtld_map.l_info);
  _dl_setup_hash (&_dl_rtld_map);

/* Don't bother trying to work out how ld.so is mapped in memory.  */
  _dl_rtld_map.l_map_start = ~0;
  _dl_rtld_map.l_map_end = ~0;

  /* 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.  */
  start_addr =  _dl_sysdep_start (arg, &dl_main);

  if (HP_TIMING_AVAIL)
    {
      hp_timing_t end_time;

      /* Get the current time.  */
      HP_TIMING_NOW (end_time);

      /* Compute the difference.  */
      HP_TIMING_DIFF (rtld_total_time, start_time, end_time);
    }

  if (_dl_debug_statistics)
    print_statistics ();

  return start_addr;
}

/* 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
{
  int doexit;
};

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

  _dl_relocate_object (args->l, args->l->l_scope,
		       args->lazy, 0);
}

static void
map_doit (void *a)
{
  struct map_args *args = (struct map_args *) a;
  args->main_map = _dl_map_object (NULL, args->str, 0, 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 (_dl_loaded, 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 = _dl_loaded->l_searchlist.r_nlist;

  while (n-- > 0)
    if (_dl_name_match_p (name, _dl_loaded->l_searchlist.r_list[n]))
      return _dl_loaded->l_searchlist.r_list[n];

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

static int
match_version (const char *string, struct link_map *map)
{
  const char *strtab = (const void *) 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;
}

static const char *library_path;	/* The library search path.  */
static const char *preloadlist;		/* The list preloaded objects.  */
static int version_info;		/* Nonzero if information about
					   versions has to be printed.  */

static void
dl_main (const ElfW(Phdr) *phdr,
	 ElfW(Half) phent,
	 ElfW(Addr) *user_entry)
{
  const ElfW(Phdr) *ph;
  enum mode mode;
  struct link_map **preloads;
  unsigned int npreloads;
  size_t file_size;
  char *file;
  int has_interp = 0;
  unsigned int i;
  int rtld_is_main = 0;
  hp_timing_t start;
  hp_timing_t stop;
  hp_timing_t diff;

  /* Process the environment variable which control the behaviour.  */
  process_envvars (&mode, &_dl_lazy);

  /* 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.  */
      rtld_is_main = 1;

      /* 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;
	    _dl_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 if (! strcmp (_dl_argv[1], "--library-path") && _dl_argc > 2)
	  {
	    library_path = _dl_argv[2];

	    _dl_skip_args += 2;
	    _dl_argc -= 2;
	    _dl_argv += 2;
	  }
	else if (! strcmp (_dl_argv[1], "--inhibit-rpath") && _dl_argc > 2)
	  {
	    _dl_inhibit_rpath = _dl_argv[2];

	    _dl_skip_args += 2;
	    _dl_argc -= 2;
	    _dl_argv += 2;
	  }
	else
	  break;

      /* If we have no further argument the program was called incorrectly.
	 Grant the user some education.  */
      if (_dl_argc < 2)
	_dl_sysdep_fatal ("\
Usage: ld.so [OPTION]... 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\
\n\
  --list                list all dependencies and how they are resolved\n\
  --verify              verify that given object really is a dynamically linked\n\
                        object we get handle\n\
  --library-path PATH   use given PATH instead of content of the environment\n\
                        variable LD_LIBRARY_PATH\n\
  --inhibit-rpath LIST  ignore RPATH information in object names in LIST\n",
			  NULL);

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

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

      if (__builtin_expect (mode, normal) == verify)
	{
	  char *err_str = NULL;
	  struct map_args args;

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

	  HP_TIMING_DIFF (load_time, start, stop);
	}

      phdr = _dl_loaded->l_phdr;
      phent = _dl_loaded->l_phnum;
      /* We overwrite here a pointer to a malloc()ed string.  But since
	 the malloc() implementation used at this point is the dummy
	 implementations which has no real free() function it does not
	 makes sense to free the old string first.  */
      _dl_loaded->l_name = (char *) "";
      *user_entry = _dl_loaded->l_entry;
    }
  else
    {
      /* Create a link_map for the executable itself.
	 This will be what dlopen on "" returns.  */
      _dl_new_object ((char *) "", "", lt_executable, NULL);
      if (_dl_loaded == NULL)
	_dl_sysdep_fatal ("cannot allocate memory for link map\n", NULL);
      _dl_loaded->l_phdr = phdr;
      _dl_loaded->l_phnum = phent;
      _dl_loaded->l_entry = *user_entry;
      _dl_loaded->l_opencount = 1;

      /* At this point we are in a bit of trouble.  We would have to
	 fill in the values for l_dev and l_ino.  But in general we
	 do not know where the file is.  We also do not handle AT_EXECFD
	 even if it would be passed up.

	 We leave the values here defined to 0.  This is normally no
	 problem as the program code itself is normally no shared
	 object and therefore cannot be loaded dynamically.  Nothing
	 prevent the use of dynamic binaries and in these situations
	 we might get problems.  We might not be able to find out
	 whether the object is already loaded.  But since there is no
	 easy way out and because the dynamic binary must also not
	 have an SONAME we ignore this program for now.  If it becomes
	 a problem we can force people using SONAMEs.  */

      /* We delay initializing the path structure until we got the dynamic
	 information for the program.  */
    }

  /* It is not safe to load stuff after the main program.  */
  _dl_loaded->l_map_end = ~0;
  /* Perhaps the executable has no PT_LOAD header entries at all.  */
  _dl_loaded->l_map_start = ~0;

  /* Scan the program header table for the dynamic section.  */
  for (ph = phdr; ph < &phdr[phent]; ++ph)
    switch (ph->p_type)
      {
      case PT_PHDR:
	/* Find out the load address.  */
	_dl_loaded->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
	break;
      case PT_DYNAMIC:
	/* This tells us where to find the dynamic section,
	   which tells us everything we need to do.  */
	_dl_loaded->l_ld = (void *) _dl_loaded->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 *) _dl_loaded->l_addr
				 + ph->p_vaddr);
	_dl_rtld_libname.next = NULL;
	_dl_rtld_map.l_libname = &_dl_rtld_libname;

	/* Ordinarilly, we would get additional names for the loader from
	   our DT_SONAME.  This can't happen if we were actually linked as
	   a static executable (detect this case when we have no DYNAMIC).
	   If so, assume the filename component of the interpreter path to
	   be our SONAME, and add it to our name list.  */
	if (_dl_rtld_map.l_ld == NULL)
	  {
	    char *p = strrchr (_dl_rtld_libname.name, '/');
	    if (p)
	      {
		_dl_rtld_libname2.name = p+1;
		_dl_rtld_libname2.next = NULL;
		_dl_rtld_libname.next = &_dl_rtld_libname2;
	      }
	  }

	has_interp = 1;
	break;
      case PT_LOAD:
	/* Remember where the main program starts in memory.  */
	{
	  ElfW(Addr) mapstart;
	  mapstart = _dl_loaded->l_addr + (ph->p_vaddr & ~(ph->p_align - 1));
	  if (_dl_loaded->l_map_start > mapstart)
	    _dl_loaded->l_map_start = mapstart;
	}
	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 (! rtld_is_main)
    {
      /* Extract the contents of the dynamic section for easy access.  */
      elf_get_dynamic_info (_dl_loaded->l_ld, _dl_loaded->l_addr,
			    _dl_loaded->l_info);
      if (_dl_loaded->l_info[DT_HASH])
	/* Set up our cache of pointers into the hash table.  */
	_dl_setup_hash (_dl_loaded);
    }

  if (__builtin_expect (mode, normal) == verify)
    {
      /* We were called just to verify that this is a dynamic
	 executable using us as the program interpreter.  Exit with an
	 error if we were not able to load the binary or no interpreter
	 is specified (i.e., this is no dynamically linked binary.  */
      if (_dl_loaded->l_ld == NULL)
	_exit (1);

      /* We allow here some platform specific code.  */
#ifdef DISTINGUISH_LIB_VERSIONS
      DISTINGUISH_LIB_VERSIONS;
#endif
      _exit (has_interp ? 0 : 2);
    }

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

  /* 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 _dl_loaded.  */
  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;
  _dl_loaded->l_next = &_dl_rtld_map;
  _dl_rtld_map.l_prev = _dl_loaded;

  /* 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;

  if (preloadlist)
    {
      /* The LD_PRELOAD environment variable gives list of libraries
	 separated by white space or colons 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;

      HP_TIMING_NOW (start);

      while ((p = strsep (&list, " :")) != NULL)
	if (p[0] != '\0'
	    && (! __libc_enable_secure || strchr (p, '/') == NULL))
	  {
	    struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
						       lt_library, 0);
	    if (new_map->l_opencount == 1)
	      /* It is no duplicate.  */
	      ++npreloads;
	  }

      HP_TIMING_NOW (stop);
      HP_TIMING_DIFF (diff, start, stop);
      HP_TIMING_ACCUM_NT (load_time, diff);
    }

  /* 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 - 1] != '\t'
	  && file[file_size - 1] != '\n' && file[file_size - 1] != ':')
	{
	  problem = &file[file_size];
	  while (problem > file && problem[-1] != ' ' && problem[-1] != '\t'
		 && problem[-1] != '\n' && problem[-1] != ':')
	    --problem;

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

      HP_TIMING_NOW (start);

      if (file != problem)
	{
	  char *p;
	  runp = file;
	  while ((p = strsep (&runp, ": \t\n")) != NULL)
	    if (p[0] != '\0')
	      {
		struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
							   lt_library, 0);
		if (new_map->l_opencount == 1)
		  /* It is no duplicate.  */
		  ++npreloads;
	      }
	}

      if (problem != NULL)
	{
	  char *p = strndupa (problem, file_size - (problem - file));
	  struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
						     lt_library, 0);
	  if (new_map->l_opencount == 1)
	    /* It is no duplicate.  */
	    ++npreloads;
	}

      HP_TIMING_NOW (stop);
      HP_TIMING_DIFF (diff, start, stop);
      HP_TIMING_ACCUM_NT (load_time, diff);

      /* 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;
      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);
    }

  /* 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.  */
  HP_TIMING_NOW (start);
  _dl_map_object_deps (_dl_loaded, preloads, npreloads, mode == trace, 0);
  HP_TIMING_NOW (stop);
  HP_TIMING_DIFF (diff, start, stop);
  HP_TIMING_ACCUM_NT (load_time, diff);

  /* Mark all objects as being in the global scope.  */
  for (i = _dl_loaded->l_searchlist.r_nlist; i > 0; )
    _dl_loaded->l_searchlist.r_list[--i]->l_global = 1;

#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 (__builtin_expect (_dl_rtld_map.l_opencount, 2) > 1)
    {
      /* 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.  */
      i = 1;
      while (_dl_loaded->l_searchlist.r_list[i] != &_dl_rtld_map)
	++i;
      _dl_rtld_map.l_prev = _dl_loaded->l_searchlist.r_list[i - 1];
      _dl_rtld_map.l_next = (i + 1 < _dl_loaded->l_searchlist.r_nlist
			     ? _dl_loaded->l_searchlist.r_list[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;
    _dl_receive_error (print_missing_version, version_check_doit, &args);
  }

  if (__builtin_expect (mode, normal) != 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.  */
      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_word (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 (__builtin_expect (mode, trace) != trace)
	for (i = 1; i < _dl_argc; ++i)
	  {
	    const ElfW(Sym) *ref = NULL;
	    ElfW(Addr) loadbase = _dl_lookup_symbol (_dl_argv[i], &ref,
						     _dl_loaded->l_scope,
						     "argument",
						     ELF_MACHINE_JMP_SLOT);
	    char buf[20], *bp;
	    buf[sizeof buf - 1] = '\0';
	    bp = _itoa_word (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_word (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 (_dl_lazy >= 0)
	    {
	      /* We have to do symbol dependency testing.  */
	      struct relocate_args args;
	      struct link_map *l;

	      args.lazy = _dl_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);
		    }
		  l = l->l_prev;
		} while (l);
	    }

#define VERNEEDTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
	  if (version_info)
	    {
	      /* 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;
		  ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG];
		  ElfW(Verneed) *ent;

		  if (dyn == NULL)
		    continue;

		  strtab = (const void *) map->l_info[DT_STRTAB]->d_un.d_ptr;
		  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;
    int consider_profiling = _dl_profile != NULL;
    hp_timing_t start;
    hp_timing_t stop;
    hp_timing_t add;

    /* If we are profiling we also must do lazy reloaction.  */
    _dl_lazy |= consider_profiling;

    l = _dl_loaded;
    while (l->l_next)
      l = l->l_next;

    HP_TIMING_NOW (start);
    do
      {
	if (l != &_dl_rtld_map)
	  _dl_relocate_object (l, l->l_scope, _dl_lazy, consider_profiling);

	l = l->l_prev;
      }
    while (l);
    HP_TIMING_NOW (stop);

    HP_TIMING_DIFF (relocate_time, start, stop);

    /* 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.  */
	HP_TIMING_NOW (start);
	_dl_relocate_object (&_dl_rtld_map, _dl_loaded->l_scope, 0, 0);
	HP_TIMING_NOW (stop);
	HP_TIMING_DIFF (add, start, stop);
	HP_TIMING_ACCUM_NT (relocate_time, add);
      }
  }

  /* Now set up the variable which helps the assembler startup code.  */
  _dl_main_searchlist = &_dl_loaded->l_searchlist;
  _dl_global_scope[0] = &_dl_loaded->l_searchlist;

  /* Safe the information about the original global scope list since
     we need it in the memory handling later.  */
  _dl_initial_searchlist = *_dl_main_searchlist;

  {
    /* 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 ();
  }

#ifndef MAP_COPY
  /* We must munmap() the cache file.  */
  _dl_unload_cache ();
#endif

  /* 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);
}

/* Nonzero if any of the debugging options is enabled.  */
static int any_debug;

/* Process the string given as the parameter which explains which debugging
   options are enabled.  */
static void
process_dl_debug (const char *dl_debug)
{
  size_t len;
#define separators " ,:"
  do
    {
      len = 0;
      /* Skip separating white spaces and commas.  */
      dl_debug += strspn (dl_debug, separators);
      if (*dl_debug != '\0')
	{
	  len = strcspn (dl_debug, separators);

	  switch (len)
	    {
	    case 3:
	      /* This option is not documented since it is not generally
		 useful.  */
	      if (memcmp (dl_debug, "all", 3) == 0)
		{
		  _dl_debug_libs = 1;
		  _dl_debug_impcalls = 1;
		  _dl_debug_reloc = 1;
		  _dl_debug_files = 1;
		  _dl_debug_symbols = 1;
		  _dl_debug_bindings = 1;
		  _dl_debug_versions = 1;
		  any_debug = 1;
		  continue;
		}
	      break;

	    case 4:
	      if (memcmp (dl_debug, "help", 4) == 0)
		{
		  _dl_sysdep_message ("\
Valid options for the LD_DEBUG environment variable are:\n\
\n\
  bindings  display information about symbol binding\n\
  files     display processing of files and libraries\n\
  help      display this help message and exit\n\
  libs      display library search paths\n\
  reloc     display relocation processing\n\
  symbols   display symbol table processing\n\
  versions  display version dependencies\n\
\n\
To direct the debugging output into a file instead of standard output\n\
a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n",
				  NULL);
		  _exit (0);
		}

	      if (memcmp (dl_debug, "libs", 4) == 0)
		{
		  _dl_debug_libs = 1;
		  _dl_debug_impcalls = 1;
		  any_debug = 1;
		  continue;
		}
	      break;

	    case 5:
	      if (memcmp (dl_debug, "reloc", 5) == 0)
		{
		  _dl_debug_reloc = 1;
		  _dl_debug_impcalls = 1;
		  any_debug = 1;
		  continue;
		}

	      if (memcmp (dl_debug, "files", 5) == 0)
		{
		  _dl_debug_files = 1;
		  _dl_debug_impcalls = 1;
		  any_debug = 1;
		  continue;
		}
	      break;

	    case 7:
	      if (memcmp (dl_debug, "symbols", 7) == 0)
		{
		  _dl_debug_symbols = 1;
		  _dl_debug_impcalls = 1;
		  any_debug = 1;
		  continue;
		}
	      break;

	    case 8:
	      if (memcmp (dl_debug, "bindings", 8) == 0)
		{
		  _dl_debug_bindings = 1;
		  _dl_debug_impcalls = 1;
		  any_debug = 1;
		  continue;
		}

	      if (memcmp (dl_debug, "versions", 8) == 0)
		{
		  _dl_debug_versions = 1;
		  _dl_debug_impcalls = 1;
		  any_debug = 1;
		  continue;
		}
	      break;

	    case 10:
	      if (memcmp (dl_debug, "statistics", 10) == 0)
		{
		  _dl_debug_statistics = 1;
		  continue;
		}
	      break;

	    default:
	      break;
	    }

	  {
	    /* Display a warning and skip everything until next separator.  */
	    char *startp = strndupa (dl_debug, len);
	    _dl_sysdep_error ("warning: debug option `", startp,
			      "' unknown; try LD_DEBUG=help\n", NULL);
	    break;
	  }
	}
    }
  while (*(dl_debug += len) != '\0');
}

/* Process all environments variables the dynamic linker must recognize.
   Since all of them start with `LD_' we are a bit smarter while finding
   all the entries.  */
static void
process_envvars (enum mode *modep, int *lazyp)
{
  char **runp = NULL;
  char *envline;
  enum mode mode = normal;
  int bind_now = 0;
  char *debug_output = NULL;

  /* This is the default place for profiling data file.  */
  _dl_profile_output = "/var/tmp";

  while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
    {
      size_t len = strcspn (envline, "=") - 3;

      switch (len)
	{
	case 4:
	  /* Warning level, verbose or not.  */
	  if (memcmp (&envline[3], "WARN", 4) == 0)
	    _dl_verbose = envline[8] != '\0';
	  break;

	case 5:
	  /* Debugging of the dynamic linker?  */
	  if (memcmp (&envline[3], "DEBUG", 5) == 0)
	    process_dl_debug (&envline[9]);
	  break;

	case 7:
	  /* Print information about versions.  */
	  if (memcmp (&envline[3], "VERBOSE", 7) == 0)
	    {
	      version_info = envline[11] != '\0';
	      break;
	    }

	  /* List of objects to be preloaded.  */
	  if (memcmp (&envline[3], "PRELOAD", 7) == 0)
	    {
	      preloadlist = &envline[11];
	      break;
	    }

	  /* Which shared object shall be profiled.  */
	  if (memcmp (&envline[3], "PROFILE", 7) == 0)
	    {
	      _dl_profile = &envline[11];
	      if (*_dl_profile == '\0')
		_dl_profile = NULL;
	    }
	  break;

	case 8:
	  /* Do we bind early?  */
	  if (memcmp (&envline[3], "BIND_NOW", 8) == 0)
	    bind_now = envline[12] != '\0';
	  break;

	case 9:
	  /* Test whether we want to see the content of the auxiliary
	     array passed up from the kernel.  */
	  if (memcmp (&envline[3], "SHOW_AUXV", 9) == 0)
	    _dl_show_auxv ();
	  break;

	case 10:
	  /* Mask for the important hardware capabilities.  */
	  if (memcmp (&envline[3], "HWCAP_MASK", 10) == 0)
	    _dl_hwcap_mask = strtoul (&envline[14], NULL, 0);
	  break;

	case 11:
	  /* Path where the binary is found.  */
	  if (!__libc_enable_secure
	      && memcmp (&envline[3], "ORIGIN_PATH", 11) == 0)
	    _dl_origin_path = &envline[15];
	  break;

	case 12:
	  /* Where to place the profiling data file.  */
	  if (memcmp (&envline[3], "DEBUG_OUTPUT", 12) == 0)
	    {
	      debug_output = &envline[16];
	      break;
	    }

	  /* The library search path.  */
	  if (memcmp (&envline[3], "LIBRARY_PATH", 12) == 0)
	    library_path = &envline[16];
	  break;

	case 14:
	  /* Where to place the profiling data file.  */
	  if (!__libc_enable_secure
	      && memcmp (&envline[3], "PROFILE_OUTPUT", 14) == 0)
	    {
	      _dl_profile_output = &envline[18];
	      if (*_dl_profile_output == '\0')
		_dl_profile_output = "/var/tmp";
	    }
	  break;

	case 20:
	  /* The mode of the dynamic linker can be set.  */
	  if (memcmp (&envline[3], "TRACE_LOADED_OBJECTS", 20) == 0)
	    mode = trace;
	  break;

	  /* We might have some extra environment variable to handle.  This
	     is tricky due to the pre-processing of the length of the name
	     in the switch statement here.  The code here assumes that added
	     environment variables have a different length.  */
#ifdef EXTRA_LD_ENVVARS
	  EXTRA_LD_ENVVARS
#endif
	}
    }

  /* Extra security for SUID binaries.  Remove all dangerous environment
     variables.  */
  if (__libc_enable_secure)
    {
      static const char *unsecure_envvars[] =
      {
#ifdef EXTRA_UNSECURE_ENVVARS
	EXTRA_UNSECURE_ENVVARS
#endif
      };
      size_t cnt;

      if (preloadlist != NULL)
	unsetenv ("LD_PRELOAD");
      if (library_path != NULL)
	unsetenv ("LD_LIBRARY_PATH");

      for (cnt = 0;
	   cnt < sizeof (unsecure_envvars) / sizeof (unsecure_envvars[0]);
	   ++cnt)
	unsetenv (unsecure_envvars[cnt]);
    }

  /* If we have to run the dynamic linker in debugging mode and the
     LD_DEBUG_OUTPUT environment variable is given, we write the debug
     messages to this file.  */
  if (any_debug && debug_output != NULL && !__libc_enable_secure)
    {
      size_t name_len = strlen (debug_output);
      char buf[name_len + 12];
      char *startp;

      buf[name_len + 11] = '\0';
      startp = _itoa_word (__getpid (), &buf[name_len + 11], 10, 0);
      *--startp = '.';
      startp = memcpy (startp - name_len, debug_output, name_len);

      _dl_debug_fd = __open (startp, O_WRONLY | O_APPEND | O_CREAT, 0666);
      if (_dl_debug_fd == -1)
	/* We use standard output if opening the file failed.  */
	_dl_debug_fd = STDOUT_FILENO;
    }

  /* LAZY is determined by the environment variable LD_WARN and
     LD_BIND_NOW if we trace the binary.  */
  if (__builtin_expect (mode, normal) == trace)
    *lazyp = _dl_verbose ? !bind_now : -1;
  else
    *lazyp = !bind_now;

  *modep = mode;
}


/* Print the various times we collected.  */
static void
print_statistics (void)
{
  char buf[200];
  char *cp;
  char *wp;

  /* Total time rtld used.  */
  if (HP_TIMING_AVAIL)
    {
      HP_TIMING_PRINT (buf, sizeof (buf), rtld_total_time);
      _dl_debug_message (1, "\nruntime linker statistics:\n"
			 "  total startup time in dynamic loader: ",
			 buf, "\n", NULL);
    }

  /* Print relocation statistics.  */
  if (HP_TIMING_AVAIL)
    {
      HP_TIMING_PRINT (buf, sizeof (buf), relocate_time);
      _dl_debug_message (1, "            time needed for relocation: ", buf,
			 NULL);
      cp = _itoa_word ((1000 * relocate_time) / rtld_total_time,
		       buf + sizeof (buf), 10, 0);
      wp = buf;
      switch (buf + sizeof (buf) - cp)
	{
	case 3:
	  *wp++ = *cp++;
	case 2:
	  *wp++ = *cp++;
	case 1:
	  *wp++ = '.';
	  *wp++ = *cp++;
	}
      *wp = '\0';
      _dl_debug_message (0, " (", buf, "%)\n", NULL);
    }

  buf[sizeof (buf) - 1] = '\0';
  _dl_debug_message (1, "                 number of relocations: ",
		     _itoa_word (_dl_num_relocations,
				 buf + sizeof (buf) - 1, 10, 0),
		     "\n", NULL);

  /* Time spend while loading the object and the dependencies.  */
  if (HP_TIMING_AVAIL)
    {
      HP_TIMING_PRINT (buf, sizeof (buf), load_time);
      _dl_debug_message (1, "           time needed to load objects: ", buf,
			 NULL);
      cp = _itoa_word ((1000 * load_time) / rtld_total_time,
		       buf + sizeof (buf), 10, 0);
      wp = buf;
      switch (buf + sizeof (buf) - cp)
	{
	case 3:
	  *wp++ = *cp++;
	case 2:
	  *wp++ = *cp++;
	case 1:
	  *wp++ = '.';
	  *wp++ = *cp++;
	}
      *wp = '\0';
      _dl_debug_message (0, " (", buf, "%)\n", NULL);
    }
}