aboutsummaryrefslogtreecommitdiff
path: root/gold/fileread.cc
blob: c4ab6b7d04e9d3d3c3971466c424f6029c681913 (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
// fileread.cc -- read files for gold

// Copyright (C) 2006-2019 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.

// This program 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 General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.

#include "gold.h"

#include <cstring>
#include <cerrno>
#include <climits>
#include <fcntl.h>
#include <unistd.h>

#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif

#ifdef HAVE_READV
#include <sys/uio.h>
#endif

#include <sys/stat.h>
#include "filenames.h"

#include "debug.h"
#include "parameters.h"
#include "options.h"
#include "dirsearch.h"
#include "target.h"
#include "binary.h"
#include "descriptors.h"
#include "gold-threads.h"
#include "fileread.h"

// For systems without mmap support.
#ifndef HAVE_MMAP
# define mmap gold_mmap
# define munmap gold_munmap
# ifndef MAP_FAILED
#  define MAP_FAILED (reinterpret_cast<void*>(-1))
# endif
# ifndef PROT_READ
#  define PROT_READ 0
# endif
# ifndef MAP_PRIVATE
#  define MAP_PRIVATE 0
# endif

# ifndef ENOSYS
#  define ENOSYS EINVAL
# endif

static void *
gold_mmap(void *, size_t, int, int, int, off_t)
{
  errno = ENOSYS;
  return MAP_FAILED;
}

static int
gold_munmap(void *, size_t)
{
  errno = ENOSYS;
  return -1;
}

#endif

#ifndef HAVE_READV
struct iovec { void* iov_base; size_t iov_len; };
ssize_t
readv(int, const iovec*, int)
{
  gold_unreachable();
}
#endif

namespace gold
{

// Get the last modified time of an unopened file.

bool
get_mtime(const char* filename, Timespec* mtime)
{
  struct stat file_stat;

  if (stat(filename, &file_stat) < 0)
    return false;
#ifdef HAVE_STAT_ST_MTIM
  mtime->seconds = file_stat.st_mtim.tv_sec;
  mtime->nanoseconds = file_stat.st_mtim.tv_nsec;
#else
  mtime->seconds = file_stat.st_mtime;
  mtime->nanoseconds = 0;
#endif
  return true;
}

// Class File_read.

// A lock for the File_read static variables.
static Lock* file_counts_lock = NULL;
static Initialize_lock file_counts_initialize_lock(&file_counts_lock);

// The File_read static variables.
unsigned long long File_read::total_mapped_bytes;
unsigned long long File_read::current_mapped_bytes;
unsigned long long File_read::maximum_mapped_bytes;

// Class File_read::View.

File_read::View::~View()
{
  gold_assert(!this->is_locked());
  switch (this->data_ownership_)
    {
    case DATA_ALLOCATED_ARRAY:
      free(const_cast<unsigned char*>(this->data_));
      break;
    case DATA_MMAPPED:
      if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
	gold_warning(_("munmap failed: %s"), strerror(errno));
      if (!parameters->options_valid() || parameters->options().stats())
	{
	  file_counts_initialize_lock.initialize();
	  Hold_optional_lock hl(file_counts_lock);
	  File_read::current_mapped_bytes -= this->size_;
	}
      break;
    case DATA_NOT_OWNED:
      break;
    default:
      gold_unreachable();
    }
}

void
File_read::View::lock()
{
  ++this->lock_count_;
}

void
File_read::View::unlock()
{
  gold_assert(this->lock_count_ > 0);
  --this->lock_count_;
}

bool
File_read::View::is_locked()
{
  return this->lock_count_ > 0;
}

// Class File_read.

File_read::~File_read()
{
  gold_assert(this->token_.is_writable());
  if (this->is_descriptor_opened_)
    {
      release_descriptor(this->descriptor_, true);
      this->descriptor_ = -1;
      this->is_descriptor_opened_ = false;
    }
  this->name_.clear();
  this->clear_views(CLEAR_VIEWS_ALL);
}

// Open the file.

bool
File_read::open(const Task* task, const std::string& name)
{
  gold_assert(this->token_.is_writable()
	      && this->descriptor_ < 0
	      && !this->is_descriptor_opened_
	      && this->name_.empty());
  this->name_ = name;

  this->descriptor_ = open_descriptor(-1, this->name_.c_str(),
				      O_RDONLY);

  if (this->descriptor_ >= 0)
    {
      this->is_descriptor_opened_ = true;
      struct stat s;
      if (::fstat(this->descriptor_, &s) < 0)
	gold_error(_("%s: fstat failed: %s"),
		   this->name_.c_str(), strerror(errno));
      this->size_ = s.st_size;
      gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
		 this->name_.c_str());
      this->token_.add_writer(task);
    }

  return this->descriptor_ >= 0;
}

// Open the file with the contents in memory.

bool
File_read::open(const Task* task, const std::string& name,
		const unsigned char* contents, off_t size)
{
  gold_assert(this->token_.is_writable()
	      && this->descriptor_ < 0
	      && !this->is_descriptor_opened_
	      && this->name_.empty());
  this->name_ = name;
  this->whole_file_view_ = new View(0, size, contents, 0, false,
				    View::DATA_NOT_OWNED);
  this->add_view(this->whole_file_view_);
  this->size_ = size;
  this->token_.add_writer(task);
  return true;
}

// Reopen a descriptor if necessary.

void
File_read::reopen_descriptor()
{
  if (!this->is_descriptor_opened_)
    {
      this->descriptor_ = open_descriptor(this->descriptor_,
					  this->name_.c_str(),
					  O_RDONLY);
      if (this->descriptor_ < 0)
	gold_fatal(_("could not reopen file %s"), this->name_.c_str());
      this->is_descriptor_opened_ = true;
    }
}

// Release the file.  This is called when we are done with the file in
// a Task.

void
File_read::release()
{
  gold_assert(this->is_locked());

  if (!parameters->options_valid() || parameters->options().stats())
    {
      file_counts_initialize_lock.initialize();
      Hold_optional_lock hl(file_counts_lock);
      File_read::total_mapped_bytes += this->mapped_bytes_;
      File_read::current_mapped_bytes += this->mapped_bytes_;
      if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
	File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
    }

  this->mapped_bytes_ = 0;

  // Only clear views if there is only one attached object.  Otherwise
  // we waste time trying to clear cached archive views.  Similarly
  // for releasing the descriptor.
  if (this->object_count_ <= 1)
    {
      this->clear_views(CLEAR_VIEWS_NORMAL);
      if (this->is_descriptor_opened_)
	{
	  release_descriptor(this->descriptor_, false);
	  this->is_descriptor_opened_ = false;
	}
    }

  this->released_ = true;
}

// Lock the file.

void
File_read::lock(const Task* task)
{
  gold_assert(this->released_);
  gold_debug(DEBUG_FILES, "Locking file \"%s\"", this->name_.c_str());
  this->token_.add_writer(task);
  this->released_ = false;
}

// Unlock the file.

void
File_read::unlock(const Task* task)
{
  gold_debug(DEBUG_FILES, "Unlocking file \"%s\"", this->name_.c_str());
  this->release();
  this->token_.remove_writer(task);
}

// Return whether the file is locked.

bool
File_read::is_locked() const
{
  if (!this->token_.is_writable())
    return true;
  // The file is not locked, so it should have been released.
  gold_assert(this->released_);
  return false;
}

// See if we have a view which covers the file starting at START for
// SIZE bytes.  Return a pointer to the View if found, NULL if not.
// If BYTESHIFT is not -1U, the returned View must have the specified
// byte shift; otherwise, it may have any byte shift.  If VSHIFTED is
// not NULL, this sets *VSHIFTED to a view which would have worked if
// not for the requested BYTESHIFT.

inline File_read::View*
File_read::find_view(off_t start, section_size_type size,
		     unsigned int byteshift, File_read::View** vshifted) const
{
  gold_assert(start <= this->size_
	      && (static_cast<unsigned long long>(size)
		  <= static_cast<unsigned long long>(this->size_ - start)));

  if (vshifted != NULL)
    *vshifted = NULL;

  // If we have the whole file mmapped, and the alignment is right,
  // we can return it.
  if (this->whole_file_view_)
    if (byteshift == -1U || byteshift == 0)
      return this->whole_file_view_;

  off_t page = File_read::page_offset(start);

  unsigned int bszero = 0;
  Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
								    bszero));

  while (p != this->views_.end() && p->first.first <= page)
    {
      if (p->second->start() <= start
	  && (p->second->start() + static_cast<off_t>(p->second->size())
	      >= start + static_cast<off_t>(size)))
	{
	  if (byteshift == -1U || byteshift == p->second->byteshift())
	    {
	      p->second->set_accessed();
	      return p->second;
	    }

	  if (vshifted != NULL && *vshifted == NULL)
	    *vshifted = p->second;
	}

      ++p;
    }

  return NULL;
}

// Read SIZE bytes from the file starting at offset START.  Read into
// the buffer at P.

void
File_read::do_read(off_t start, section_size_type size, void* p)
{
  ssize_t bytes;
  if (this->whole_file_view_ != NULL)
    {
      bytes = this->size_ - start;
      if (static_cast<section_size_type>(bytes) >= size)
	{
	  memcpy(p, this->whole_file_view_->data() + start, size);
	  return;
	}
    }
  else
    {
      this->reopen_descriptor();

      char *read_ptr = static_cast<char *>(p);
      off_t read_pos = start;
      size_t to_read = size;
      do
	{
	  bytes = ::pread(this->descriptor_, read_ptr, to_read, read_pos);
	  if (bytes < 0)
	    gold_fatal(_("%s: pread failed: %s"),
		       this->filename().c_str(), strerror(errno));

	  read_pos += bytes;
	  read_ptr += bytes;
	  to_read -= bytes;
	  if (to_read == 0)
	    return;
	}
      while (bytes > 0);

      bytes = size - to_read;
    }

  gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
	     this->filename().c_str(),
	     static_cast<long long>(bytes),
	     static_cast<long long>(size),
	     static_cast<long long>(start));
}

// Read data from the file.

void
File_read::read(off_t start, section_size_type size, void* p)
{
  const File_read::View* pv = this->find_view(start, size, -1U, NULL);
  if (pv != NULL)
    {
      memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
      return;
    }

  this->do_read(start, size, p);
}

// Add a new view.  There may already be an existing view at this
// offset.  If there is, the new view will be larger, and should
// replace the old view.

void
File_read::add_view(File_read::View* v)
{
  std::pair<Views::iterator, bool> ins =
    this->views_.insert(std::make_pair(std::make_pair(v->start(),
						      v->byteshift()),
				       v));
  if (ins.second)
    return;

  // There was an existing view at this offset.  It must not be large
  // enough.  We can't delete it here, since something might be using
  // it; we put it on a list to be deleted when the file is unlocked.
  File_read::View* vold = ins.first->second;
  gold_assert(vold->size() < v->size());
  if (vold->should_cache())
    {
      v->set_cache();
      vold->clear_cache();
    }
  this->saved_views_.push_back(vold);

  ins.first->second = v;
}

// Make a new view with a specified byteshift, reading the data from
// the file.

File_read::View*
File_read::make_view(off_t start, section_size_type size,
		     unsigned int byteshift, bool cache)
{
  gold_assert(size > 0);
  gold_assert(start <= this->size_
	      && (static_cast<unsigned long long>(size)
		  <= static_cast<unsigned long long>(this->size_ - start)));

  off_t poff = File_read::page_offset(start);

  section_size_type psize = File_read::pages(size + (start - poff));

  if (poff + static_cast<off_t>(psize) >= this->size_)
    {
      psize = this->size_ - poff;
      gold_assert(psize >= size);
    }

  void* p;
  View::Data_ownership ownership;
  if (byteshift != 0)
    {
      p = malloc(psize + byteshift);
      if (p == NULL)
	gold_nomem();
      memset(p, 0, byteshift);
      this->do_read(poff, psize, static_cast<unsigned char*>(p) + byteshift);
      ownership = View::DATA_ALLOCATED_ARRAY;
    }
  else
    {
      this->reopen_descriptor();
      p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE, this->descriptor_, poff);
      if (p != MAP_FAILED)
	{
	  ownership = View::DATA_MMAPPED;
	  this->mapped_bytes_ += psize;
	}
      else
	{
	  p = malloc(psize);
	  if (p == NULL)
	    gold_nomem();
	  this->do_read(poff, psize, p);
	  ownership = View::DATA_ALLOCATED_ARRAY;
	}
    }

  const unsigned char* pbytes = static_cast<const unsigned char*>(p);
  File_read::View* v = new File_read::View(poff, psize, pbytes, byteshift,
					   cache, ownership);

  this->add_view(v);

  return v;
}

// Find a View or make a new one, shifted as required by the file
// offset OFFSET and ALIGNED.

File_read::View*
File_read::find_or_make_view(off_t offset, off_t start,
			     section_size_type size, bool aligned, bool cache)
{
  // Check that start and end of the view are within the file.
  if (start > this->size_
      || (static_cast<unsigned long long>(size)
	  > static_cast<unsigned long long>(this->size_ - start)))
    gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
		 "size of file; the file may be corrupt"),
		   this->filename().c_str(),
		   static_cast<long long>(size),
		   static_cast<long long>(start));

  unsigned int byteshift;
  if (offset == 0)
    byteshift = 0;
  else
    {
      unsigned int target_size = (!parameters->target_valid()
				  ? 64
				  : parameters->target().get_size());
      byteshift = offset & ((target_size / 8) - 1);

      // Set BYTESHIFT to the number of dummy bytes which must be
      // inserted before the data in order for this data to be
      // aligned.
      if (byteshift != 0)
	byteshift = (target_size / 8) - byteshift;
    }

  // If --map-whole-files is set, make sure we have a
  // whole file view.  Options may not yet be ready, e.g.,
  // when reading a version script.  We then default to
  // --no-map-whole-files.
  if (this->whole_file_view_ == NULL
      && parameters->options_valid()
      && parameters->options().map_whole_files())
    this->whole_file_view_ = this->make_view(0, this->size_, 0, cache);

  // Try to find a View with the required BYTESHIFT.
  File_read::View* vshifted;
  File_read::View* v = this->find_view(offset + start, size,
				       aligned ? byteshift : -1U,
				       &vshifted);
  if (v != NULL)
    {
      if (cache)
	v->set_cache();
      return v;
    }

  // If VSHIFTED is not NULL, then it has the data we need, but with
  // the wrong byteshift.
  v = vshifted;
  if (v != NULL)
    {
      gold_assert(aligned);

      unsigned char* pbytes;
      pbytes = static_cast<unsigned char*>(malloc(v->size() + byteshift));
      if (pbytes == NULL)
	gold_nomem();
      memset(pbytes, 0, byteshift);
      memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());

      File_read::View* shifted_view =
	  new File_read::View(v->start(), v->size(), pbytes, byteshift,
			      cache, View::DATA_ALLOCATED_ARRAY);

      this->add_view(shifted_view);
      return shifted_view;
    }

  // Make a new view.  If we don't need an aligned view, use a
  // byteshift of 0, so that we can use mmap.
  return this->make_view(offset + start, size,
			 aligned ? byteshift : 0,
			 cache);
}

// Get a view into the file.

const unsigned char*
File_read::get_view(off_t offset, off_t start, section_size_type size,
		    bool aligned, bool cache)
{
  File_read::View* pv = this->find_or_make_view(offset, start, size,
						aligned, cache);
  return pv->data() + (offset + start - pv->start() + pv->byteshift());
}

File_view*
File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
			    bool aligned, bool cache)
{
  File_read::View* pv = this->find_or_make_view(offset, start, size,
						aligned, cache);
  pv->lock();
  return new File_view(*this, pv,
		       (pv->data()
			+ (offset + start - pv->start() + pv->byteshift())));
}

// Use readv to read COUNT entries from RM starting at START.  BASE
// must be added to all file offsets in RM.

void
File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
		    size_t count)
{
  unsigned char discard[File_read::page_size];
  iovec iov[File_read::max_readv_entries * 2];
  size_t iov_index = 0;

  off_t first_offset = rm[start].file_offset;
  off_t last_offset = first_offset;
  ssize_t want = 0;
  for (size_t i = 0; i < count; ++i)
    {
      const Read_multiple_entry& i_entry(rm[start + i]);

      if (i_entry.file_offset > last_offset)
	{
	  size_t skip = i_entry.file_offset - last_offset;
	  gold_assert(skip <= sizeof discard);

	  iov[iov_index].iov_base = discard;
	  iov[iov_index].iov_len = skip;
	  ++iov_index;

	  want += skip;
	}

      iov[iov_index].iov_base = i_entry.buffer;
      iov[iov_index].iov_len = i_entry.size;
      ++iov_index;

      want += i_entry.size;

      last_offset = i_entry.file_offset + i_entry.size;
    }

  this->reopen_descriptor();

  gold_assert(iov_index < sizeof iov / sizeof iov[0]);

  if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
    gold_fatal(_("%s: lseek failed: %s"),
	       this->filename().c_str(), strerror(errno));

  ssize_t got = ::readv(this->descriptor_, iov, iov_index);

  if (got < 0)
    gold_fatal(_("%s: readv failed: %s"),
	       this->filename().c_str(), strerror(errno));
  if (got != want)
    gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
	       this->filename().c_str(),
	       got, want, static_cast<long long>(base + first_offset));
}

// Portable IOV_MAX.

#if !defined(HAVE_READV)
#define GOLD_IOV_MAX 1
#elif defined(IOV_MAX)
#define GOLD_IOV_MAX IOV_MAX
#else
#define GOLD_IOV_MAX (File_read::max_readv_entries * 2)
#endif

// Read several pieces of data from the file.

void
File_read::read_multiple(off_t base, const Read_multiple& rm)
{
  static size_t iov_max = GOLD_IOV_MAX;
  size_t count = rm.size();
  size_t i = 0;
  while (i < count)
    {
      // Find up to MAX_READV_ENTRIES consecutive entries which are
      // less than one page apart.
      const Read_multiple_entry& i_entry(rm[i]);
      off_t i_off = i_entry.file_offset;
      off_t end_off = i_off + i_entry.size;
      size_t j;
      for (j = i + 1; j < count; ++j)
	{
	  if (j - i >= File_read::max_readv_entries || j - i >= iov_max / 2)
	    break;
	  const Read_multiple_entry& j_entry(rm[j]);
	  off_t j_off = j_entry.file_offset;
	  gold_assert(j_off >= end_off);
	  off_t j_end_off = j_off + j_entry.size;
	  if (j_end_off - end_off >= File_read::page_size)
	    break;
	  end_off = j_end_off;
	}

      if (j == i + 1)
	this->read(base + i_off, i_entry.size, i_entry.buffer);
      else
	{
	  File_read::View* view = this->find_view(base + i_off,
						  end_off - i_off,
						  -1U, NULL);
	  if (view == NULL)
	    this->do_readv(base, rm, i, j - i);
	  else
	    {
	      const unsigned char* v = (view->data()
					+ (base + i_off - view->start()
					   + view->byteshift()));
	      for (size_t k = i; k < j; ++k)
		{
		  const Read_multiple_entry& k_entry(rm[k]);
		  gold_assert((convert_to_section_size_type(k_entry.file_offset
							   - i_off)
			       + k_entry.size)
			      <= convert_to_section_size_type(end_off
							      - i_off));
		  memcpy(k_entry.buffer,
			 v + (k_entry.file_offset - i_off),
			 k_entry.size);
		}
	    }
	}

      i = j;
    }
}

// Mark all views as no longer cached.

void
File_read::clear_view_cache_marks()
{
  // Just ignore this if there are multiple objects associated with
  // the file.  Otherwise we will wind up uncaching and freeing some
  // views for other objects.
  if (this->object_count_ > 1)
    return;

  for (Views::iterator p = this->views_.begin();
       p != this->views_.end();
       ++p)
    p->second->clear_cache();
  for (Saved_views::iterator p = this->saved_views_.begin();
       p != this->saved_views_.end();
       ++p)
    (*p)->clear_cache();
}

// Remove all the file views.  For a file which has multiple
// associated objects (i.e., an archive), we keep accessed views
// around until next time, in the hopes that they will be useful for
// the next object.

void
File_read::clear_views(Clear_views_mode mode)
{
  bool keep_files_mapped = (parameters->options_valid()
			    && parameters->options().keep_files_mapped());
  Views::iterator p = this->views_.begin();
  while (p != this->views_.end())
    {
      bool should_delete;
      if (p->second->is_locked() || p->second->is_permanent_view())
	should_delete = false;
      else if (mode == CLEAR_VIEWS_ALL)
	should_delete = true;
      else if ((p->second->should_cache()
		|| p->second == this->whole_file_view_)
	       && keep_files_mapped)
	should_delete = false;
      else if (this->object_count_ > 1
	       && p->second->accessed()
	       && mode != CLEAR_VIEWS_ARCHIVE)
	should_delete = false;
      else
	should_delete = true;

      if (should_delete)
	{
	  if (p->second == this->whole_file_view_)
	    this->whole_file_view_ = NULL;
	  delete p->second;

	  // map::erase invalidates only the iterator to the deleted
	  // element.
	  Views::iterator pe = p;
	  ++p;
	  this->views_.erase(pe);
	}
      else
	{
	  p->second->clear_accessed();
	  ++p;
	}
    }

  Saved_views::iterator q = this->saved_views_.begin();
  while (q != this->saved_views_.end())
    {
      if (!(*q)->is_locked())
	{
	  delete *q;
	  q = this->saved_views_.erase(q);
	}
      else
	{
	  gold_assert(mode != CLEAR_VIEWS_ALL);
	  ++q;
	}
    }
}

// Print statistical information to stderr.  This is used for --stats.

void
File_read::print_stats()
{
  fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
	  program_name, File_read::total_mapped_bytes);
  fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
	  program_name, File_read::maximum_mapped_bytes);
}

// Class File_view.

File_view::~File_view()
{
  gold_assert(this->file_.is_locked());
  this->view_->unlock();
}

// Class Input_file.

// Create a file given just the filename.

Input_file::Input_file(const char* name)
  : found_name_(), file_(), is_in_sysroot_(false), format_(FORMAT_NONE)
{
  this->input_argument_ =
    new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
			    "", false, Position_dependent_options());
}

// Create a file for testing.

Input_file::Input_file(const Task* task, const char* name,
		       const unsigned char* contents, off_t size)
  : file_()
{
  this->input_argument_ =
    new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
			    "", false, Position_dependent_options());
  bool ok = this->file_.open(task, name, contents, size);
  gold_assert(ok);
}

// Return the position dependent options in force for this file.

const Position_dependent_options&
Input_file::options() const
{
  return this->input_argument_->options();
}

// Return the name given by the user.  For -lc this will return "c".

const char*
Input_file::name() const
{
  return this->input_argument_->name();
}

// Return whether this file is in a system directory.

bool
Input_file::is_in_system_directory() const
{
  if (this->is_in_sysroot())
    return true;
  return parameters->options().is_in_system_directory(this->filename());
}

// Return whether we are only reading symbols.

bool
Input_file::just_symbols() const
{
  return this->input_argument_->just_symbols();
}

// Return whether this is a file that we will search for in the list
// of directories.

bool
Input_file::will_search_for() const
{
  return (!IS_ABSOLUTE_PATH(this->input_argument_->name())
	  && (this->input_argument_->is_lib()
	      || this->input_argument_->is_searched_file()
	      || this->input_argument_->extra_search_path() != NULL));
}

// Return the file last modification time.  Calls gold_fatal if the stat
// system call failed.

Timespec
File_read::get_mtime()
{
  struct stat file_stat;
  this->reopen_descriptor();

  if (fstat(this->descriptor_, &file_stat) < 0)
    gold_fatal(_("%s: stat failed: %s"), this->name_.c_str(),
	       strerror(errno));
#ifdef HAVE_STAT_ST_MTIM
  return Timespec(file_stat.st_mtim.tv_sec, file_stat.st_mtim.tv_nsec);
#else
  return Timespec(file_stat.st_mtime, 0);
#endif
}

// Try to find a file in the extra search dirs.  Returns true on success.

bool
Input_file::try_extra_search_path(int* pindex,
				  const Input_file_argument* input_argument,
				  std::string filename, std::string* found_name,
				  std::string* namep)
{
  if (input_argument->extra_search_path() == NULL)
    return false;

  std::string name = input_argument->extra_search_path();
  if (!IS_DIR_SEPARATOR(name[name.length() - 1]))
    name += '/';
  name += filename;

  struct stat dummy_stat;
  if (*pindex > 0 || ::stat(name.c_str(), &dummy_stat) < 0)
    return false;

  *found_name = filename;
  *namep = name;
  return true;
}

// Find the actual file.
// If the filename is not absolute, we assume it is in the current
// directory *except* when:
//    A) input_argument_->is_lib() is true;
//    B) input_argument_->is_searched_file() is true; or
//    C) input_argument_->extra_search_path() is not empty.
// In each, we look in extra_search_path + library_path to find
// the file location, rather than the current directory.

bool
Input_file::find_file(const Dirsearch& dirpath, int* pindex,
		      const Input_file_argument* input_argument,
		      bool* is_in_sysroot,
		      std::string* found_name, std::string* namep)
{
  std::string name;

  // Case 1: name is an absolute file, just try to open it
  // Case 2: name is relative but is_lib is false, is_searched_file is false,
  //         and extra_search_path is empty
  if (IS_ABSOLUTE_PATH(input_argument->name())
      || (!input_argument->is_lib()
	  && !input_argument->is_searched_file()
	  && input_argument->extra_search_path() == NULL))
    {
      name = input_argument->name();
      *found_name = name;
      *namep = name;
      return true;
    }
  // Case 3: is_lib is true or is_searched_file is true
  else if (input_argument->is_lib()
	   || input_argument->is_searched_file())
    {
      std::vector<std::string> names;
      names.reserve(2);
      if (input_argument->is_lib())
	{
	  std::string prefix = "lib";
	  prefix += input_argument->name();
	  if (parameters->options().is_static()
	      || !input_argument->options().Bdynamic())
	    names.push_back(prefix + ".a");
	  else
	    {
	      names.push_back(prefix + ".so");
	      names.push_back(prefix + ".a");
	    }
	}
      else
	names.push_back(input_argument->name());

      for (std::vector<std::string>::const_iterator n = names.begin();
	   n != names.end();
	   ++n)
	if (Input_file::try_extra_search_path(pindex, input_argument, *n,
					      found_name, namep))
	  return true;

      // It is not in the extra_search_path.
      name = dirpath.find(names, is_in_sysroot, pindex, found_name);
      if (name.empty())
	{
	  gold_error(_("cannot find %s%s"),
		     input_argument->is_lib() ? "-l" : "",
		     input_argument->name());
	  return false;
	}
      *namep = name;
      return true;
    }
  // Case 4: extra_search_path is not empty
  else
    {
      gold_assert(input_argument->extra_search_path() != NULL);

      if (try_extra_search_path(pindex, input_argument, input_argument->name(),
				found_name, namep))
	return true;

      // extra_search_path failed, so check the normal search-path.
      int index = *pindex;
      if (index > 0)
	--index;
      name = dirpath.find(std::vector<std::string>(1, input_argument->name()),
			  is_in_sysroot, &index, found_name);
      if (name.empty())
	{
	  gold_error(_("cannot find %s"),
		     input_argument->name());
	  return false;
	}
      *namep = name;
      *pindex = index + 1;
      return true;
    }
}

// Open the file.

bool
Input_file::open(const Dirsearch& dirpath, const Task* task, int* pindex)
{
  std::string name;
  if (!Input_file::find_file(dirpath, pindex, this->input_argument_,
			     &this->is_in_sysroot_, &this->found_name_, &name))
    return false;

  // Now that we've figured out where the file lives, try to open it.

  General_options::Object_format format =
    this->input_argument_->options().format_enum();
  bool ok;
  if (format == General_options::OBJECT_FORMAT_ELF)
    {
      ok = this->file_.open(task, name);
      this->format_ = FORMAT_ELF;
    }
  else
    {
      gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
      ok = this->open_binary(task, name);
      this->format_ = FORMAT_BINARY;
    }

  if (!ok)
    {
      gold_error(_("cannot open %s: %s"),
		 name.c_str(), strerror(errno));
      this->format_ = FORMAT_NONE;
      return false;
    }

  return true;
}

// Open a file for --format binary.

bool
Input_file::open_binary(const Task* task, const std::string& name)
{
  // In order to open a binary file, we need machine code, size, and
  // endianness.  We may not have a valid target at this point, in
  // which case we use the default target.
  parameters_force_valid_target();
  const Target& target(parameters->target());

  Binary_to_elf binary_to_elf(target.machine_code(),
			      target.get_size(),
			      target.is_big_endian(),
			      name);
  if (!binary_to_elf.convert(task))
    return false;
  return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
			  binary_to_elf.converted_size());
}

} // End namespace gold.