gold/fileread.cc

   1 // fileread.cc -- read files for gold
   2
   3 // Copyright (C) 2006-2020 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstring>
  26 #include <cerrno>
  27 #include <climits>
  28 #include <fcntl.h>
  29 #include <unistd.h>
  30
  31 #ifdef HAVE_SYS_MMAN_H
  32 #include <sys/mman.h>
  33 #endif
  34
  35 #ifdef HAVE_READV
  36 #include <sys/uio.h>
  37 #endif
  38
  39 #include <sys/stat.h>
  40 #include "filenames.h"
  41
  42 #include "debug.h"
  43 #include "parameters.h"
  44 #include "options.h"
  45 #include "dirsearch.h"
  46 #include "target.h"
  47 #include "binary.h"
  48 #include "descriptors.h"
  49 #include "gold-threads.h"
  50 #include "fileread.h"
  51
  52 // For systems without mmap support.
  53 #ifndef HAVE_MMAP
  54 # define mmap gold_mmap
  55 # define munmap gold_munmap
  56 # ifndef MAP_FAILED
  57 #  define MAP_FAILED (reinterpret_cast<void*>(-1))
  58 # endif
  59 # ifndef PROT_READ
  60 #  define PROT_READ 0
  61 # endif
  62 # ifndef MAP_PRIVATE
  63 #  define MAP_PRIVATE 0
  64 # endif
  65
  66 # ifndef ENOSYS
  67 #  define ENOSYS EINVAL
  68 # endif
  69
  70 static void *
  71 gold_mmap(void *, size_t, int, int, int, off_t)
  72 {
  73   errno = ENOSYS;
  74   return MAP_FAILED;
  75 }
  76
  77 static int
  78 gold_munmap(void *, size_t)
  79 {
  80   errno = ENOSYS;
  81   return -1;
  82 }
  83
  84 #endif
  85
  86 #ifndef HAVE_READV
  87 struct iovec { void* iov_base; size_t iov_len; };
  88 ssize_t
  89 readv(int, const iovec*, int)
  90 {
  91   gold_unreachable();
  92 }
  93 #endif
  94
  95 namespace gold
  96 {
  97
  98 // Get the last modified time of an unopened file.
  99
 100 bool
 101 get_mtime(const char* filename, Timespec* mtime)
 102 {
 103   struct stat file_stat;
 104
 105   if (stat(filename, &file_stat) < 0)
 106     return false;
 107 #ifdef HAVE_STAT_ST_MTIM
 108   mtime->seconds = file_stat.st_mtim.tv_sec;
 109   mtime->nanoseconds = file_stat.st_mtim.tv_nsec;
 110 #else
 111   mtime->seconds = file_stat.st_mtime;
 112   mtime->nanoseconds = 0;
 113 #endif
 114   return true;
 115 }
 116
 117 // Class File_read.
 118
 119 // A lock for the File_read static variables.
 120 static Lock* file_counts_lock = NULL;
 121 static Initialize_lock file_counts_initialize_lock(&file_counts_lock);
 122
 123 // The File_read static variables.
 124 unsigned long long File_read::total_mapped_bytes;
 125 unsigned long long File_read::current_mapped_bytes;
 126 unsigned long long File_read::maximum_mapped_bytes;
 127
 128 // Class File_read::View.
 129
 130 File_read::View::~View()
 131 {
 132   gold_assert(!this->is_locked());
 133   switch (this->data_ownership_)
 134     {
 135     case DATA_ALLOCATED_ARRAY:
 136       free(const_cast<unsigned char*>(this->data_));
 137       break;
 138     case DATA_MMAPPED:
 139       if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
 140         gold_warning(_("munmap failed: %s"), strerror(errno));
 141       if (!parameters->options_valid() || parameters->options().stats())
 142         {
 143           file_counts_initialize_lock.initialize();
 144           Hold_optional_lock hl(file_counts_lock);
 145           File_read::current_mapped_bytes -= this->size_;
 146         }
 147       break;
 148     case DATA_NOT_OWNED:
 149       break;
 150     default:
 151       gold_unreachable();
 152     }
 153 }
 154
 155 void
 156 File_read::View::lock()
 157 {
 158   ++this->lock_count_;
 159 }
 160
 161 void
 162 File_read::View::unlock()
 163 {
 164   gold_assert(this->lock_count_ > 0);
 165   --this->lock_count_;
 166 }
 167
 168 bool
 169 File_read::View::is_locked()
 170 {
 171   return this->lock_count_ > 0;
 172 }
 173
 174 // Class File_read.
 175
 176 File_read::~File_read()
 177 {
 178   gold_assert(this->token_.is_writable());
 179   if (this->is_descriptor_opened_)
 180     {
 181       release_descriptor(this->descriptor_, true);
 182       this->descriptor_ = -1;
 183       this->is_descriptor_opened_ = false;
 184     }
 185   this->name_.clear();
 186   this->clear_views(CLEAR_VIEWS_ALL);
 187 }
 188
 189 // Open the file.
 190
 191 bool
 192 File_read::open(const Task* task, const std::string& name)
 193 {
 194   gold_assert(this->token_.is_writable()
 195               && this->descriptor_ < 0
 196               && !this->is_descriptor_opened_
 197               && this->name_.empty());
 198   this->name_ = name;
 199
 200   this->descriptor_ = open_descriptor(-1, this->name_.c_str(),
 201                                       O_RDONLY);
 202
 203   if (this->descriptor_ >= 0)
 204     {
 205       this->is_descriptor_opened_ = true;
 206       struct stat s;
 207       if (::fstat(this->descriptor_, &s) < 0)
 208         gold_error(_("%s: fstat failed: %s"),
 209                    this->name_.c_str(), strerror(errno));
 210       this->size_ = s.st_size;
 211       gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
 212                  this->name_.c_str());
 213       this->token_.add_writer(task);
 214     }
 215
 216   return this->descriptor_ >= 0;
 217 }
 218
 219 // Open the file with the contents in memory.
 220
 221 bool
 222 File_read::open(const Task* task, const std::string& name,
 223                 const unsigned char* contents, off_t size)
 224 {
 225   gold_assert(this->token_.is_writable()
 226               && this->descriptor_ < 0
 227               && !this->is_descriptor_opened_
 228               && this->name_.empty());
 229   this->name_ = name;
 230   this->whole_file_view_ = new View(0, size, contents, 0, false,
 231                                     View::DATA_NOT_OWNED);
 232   this->add_view(this->whole_file_view_);
 233   this->size_ = size;
 234   this->token_.add_writer(task);
 235   return true;
 236 }
 237
 238 // Reopen a descriptor if necessary.
 239
 240 void
 241 File_read::reopen_descriptor()
 242 {
 243   if (!this->is_descriptor_opened_)
 244     {
 245       this->descriptor_ = open_descriptor(this->descriptor_,
 246                                           this->name_.c_str(),
 247                                           O_RDONLY);
 248       if (this->descriptor_ < 0)
 249         gold_fatal(_("could not reopen file %s"), this->name_.c_str());
 250       this->is_descriptor_opened_ = true;
 251     }
 252 }
 253
 254 // Release the file.  This is called when we are done with the file in
 255 // a Task.
 256
 257 void
 258 File_read::release()
 259 {
 260   gold_assert(this->is_locked());
 261
 262   if (!parameters->options_valid() || parameters->options().stats())
 263     {
 264       file_counts_initialize_lock.initialize();
 265       Hold_optional_lock hl(file_counts_lock);
 266       File_read::total_mapped_bytes += this->mapped_bytes_;
 267       File_read::current_mapped_bytes += this->mapped_bytes_;
 268       if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
 269         File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
 270     }
 271
 272   this->mapped_bytes_ = 0;
 273
 274   // Only clear views if there is only one attached object.  Otherwise
 275   // we waste time trying to clear cached archive views.  Similarly
 276   // for releasing the descriptor.
 277   if (this->object_count_ <= 1)
 278     {
 279       this->clear_views(CLEAR_VIEWS_NORMAL);
 280       if (this->is_descriptor_opened_)
 281         {
 282           release_descriptor(this->descriptor_, false);
 283           this->is_descriptor_opened_ = false;
 284         }
 285     }
 286
 287   this->released_ = true;
 288 }
 289
 290 // Lock the file.
 291
 292 void
 293 File_read::lock(const Task* task)
 294 {
 295   gold_assert(this->released_);
 296   gold_debug(DEBUG_FILES, "Locking file \"%s\"", this->name_.c_str());
 297   this->token_.add_writer(task);
 298   this->released_ = false;
 299 }
 300
 301 // Unlock the file.
 302
 303 void
 304 File_read::unlock(const Task* task)
 305 {
 306   gold_debug(DEBUG_FILES, "Unlocking file \"%s\"", this->name_.c_str());
 307   this->release();
 308   this->token_.remove_writer(task);
 309 }
 310
 311 // Return whether the file is locked.
 312
 313 bool
 314 File_read::is_locked() const
 315 {
 316   if (!this->token_.is_writable())
 317     return true;
 318   // The file is not locked, so it should have been released.
 319   gold_assert(this->released_);
 320   return false;
 321 }
 322
 323 // See if we have a view which covers the file starting at START for
 324 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
 325 // If BYTESHIFT is not -1U, the returned View must have the specified
 326 // byte shift; otherwise, it may have any byte shift.  If VSHIFTED is
 327 // not NULL, this sets *VSHIFTED to a view which would have worked if
 328 // not for the requested BYTESHIFT.
 329
 330 inline File_read::View*
 331 File_read::find_view(off_t start, section_size_type size,
 332                      unsigned int byteshift, File_read::View** vshifted) const
 333 {
 334   gold_assert(start <= this->size_
 335               && (static_cast<unsigned long long>(size)
 336                   <= static_cast<unsigned long long>(this->size_ - start)));
 337
 338   if (vshifted != NULL)
 339     *vshifted = NULL;
 340
 341   // If we have the whole file mmapped, and the alignment is right,
 342   // we can return it.
 343   if (this->whole_file_view_)
 344     if (byteshift == -1U || byteshift == 0)
 345       return this->whole_file_view_;
 346
 347   off_t page = File_read::page_offset(start);
 348
 349   unsigned int bszero = 0;
 350   Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
 351                                                                     bszero));
 352
 353   while (p != this->views_.end() && p->first.first <= page)
 354     {
 355       if (p->second->start() <= start
 356           && (p->second->start() + static_cast<off_t>(p->second->size())
 357               >= start + static_cast<off_t>(size)))
 358         {
 359           if (byteshift == -1U || byteshift == p->second->byteshift())
 360             {
 361               p->second->set_accessed();
 362               return p->second;
 363             }
 364
 365           if (vshifted != NULL && *vshifted == NULL)
 366             *vshifted = p->second;
 367         }
 368
 369       ++p;
 370     }
 371
 372   return NULL;
 373 }
 374
 375 // Read SIZE bytes from the file starting at offset START.  Read into
 376 // the buffer at P.
 377
 378 void
 379 File_read::do_read(off_t start, section_size_type size, void* p)
 380 {
 381   ssize_t bytes;
 382   if (this->whole_file_view_ != NULL)
 383     {
 384       bytes = this->size_ - start;
 385       if (static_cast<section_size_type>(bytes) >= size)
 386         {
 387           memcpy(p, this->whole_file_view_->data() + start, size);
 388           return;
 389         }
 390     }
 391   else
 392     {
 393       this->reopen_descriptor();
 394
 395       char *read_ptr = static_cast<char *>(p);
 396       off_t read_pos = start;
 397       size_t to_read = size;
 398       do
 399         {
 400           bytes = ::pread(this->descriptor_, read_ptr, to_read, read_pos);
 401           if (bytes < 0)
 402             gold_fatal(_("%s: pread failed: %s"),
 403                        this->filename().c_str(), strerror(errno));
 404
 405           read_pos += bytes;
 406           read_ptr += bytes;
 407           to_read -= bytes;
 408           if (to_read == 0)
 409             return;
 410         }
 411       while (bytes > 0);
 412
 413       bytes = size - to_read;
 414     }
 415
 416   gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
 417              this->filename().c_str(),
 418              static_cast<long long>(bytes),
 419              static_cast<long long>(size),
 420              static_cast<long long>(start));
 421 }
 422
 423 // Read data from the file.
 424
 425 void
 426 File_read::read(off_t start, section_size_type size, void* p)
 427 {
 428   const File_read::View* pv = this->find_view(start, size, -1U, NULL);
 429   if (pv != NULL)
 430     {
 431       memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
 432       return;
 433     }
 434
 435   this->do_read(start, size, p);
 436 }
 437
 438 // Add a new view.  There may already be an existing view at this
 439 // offset.  If there is, the new view will be larger, and should
 440 // replace the old view.
 441
 442 void
 443 File_read::add_view(File_read::View* v)
 444 {
 445   std::pair<Views::iterator, bool> ins =
 446     this->views_.insert(std::make_pair(std::make_pair(v->start(),
 447                                                       v->byteshift()),
 448                                        v));
 449   if (ins.second)
 450     return;
 451
 452   // There was an existing view at this offset.  It must not be large
 453   // enough.  We can't delete it here, since something might be using
 454   // it; we put it on a list to be deleted when the file is unlocked.
 455   File_read::View* vold = ins.first->second;
 456   gold_assert(vold->size() < v->size());
 457   if (vold->should_cache())
 458     {
 459       v->set_cache();
 460       vold->clear_cache();
 461     }
 462   this->saved_views_.push_back(vold);
 463
 464   ins.first->second = v;
 465 }
 466
 467 // Make a new view with a specified byteshift, reading the data from
 468 // the file.
 469
 470 File_read::View*
 471 File_read::make_view(off_t start, section_size_type size,
 472                      unsigned int byteshift, bool cache)
 473 {
 474   gold_assert(size > 0);
 475   gold_assert(start <= this->size_
 476               && (static_cast<unsigned long long>(size)
 477                   <= static_cast<unsigned long long>(this->size_ - start)));
 478
 479   off_t poff = File_read::page_offset(start);
 480
 481   section_size_type psize = File_read::pages(size + (start - poff));
 482
 483   if (poff + static_cast<off_t>(psize) >= this->size_)
 484     {
 485       psize = this->size_ - poff;
 486       gold_assert(psize >= size);
 487     }
 488
 489   void* p;
 490   View::Data_ownership ownership;
 491   if (byteshift != 0)
 492     {
 493       p = malloc(psize + byteshift);
 494       if (p == NULL)
 495         gold_nomem();
 496       memset(p, 0, byteshift);
 497       this->do_read(poff, psize, static_cast<unsigned char*>(p) + byteshift);
 498       ownership = View::DATA_ALLOCATED_ARRAY;
 499     }
 500   else
 501     {
 502       this->reopen_descriptor();
 503       p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE, this->descriptor_, poff);
 504       if (p != MAP_FAILED)
 505         {
 506           ownership = View::DATA_MMAPPED;
 507           this->mapped_bytes_ += psize;
 508         }
 509       else
 510         {
 511           p = malloc(psize);
 512           if (p == NULL)
 513             gold_nomem();
 514           this->do_read(poff, psize, p);
 515           ownership = View::DATA_ALLOCATED_ARRAY;
 516         }
 517     }
 518
 519   const unsigned char* pbytes = static_cast<const unsigned char*>(p);
 520   File_read::View* v = new File_read::View(poff, psize, pbytes, byteshift,
 521                                            cache, ownership);
 522
 523   this->add_view(v);
 524
 525   return v;
 526 }
 527
 528 // Find a View or make a new one, shifted as required by the file
 529 // offset OFFSET and ALIGNED.
 530
 531 File_read::View*
 532 File_read::find_or_make_view(off_t offset, off_t start,
 533                              section_size_type size, bool aligned, bool cache)
 534 {
 535   // Check that start and end of the view are within the file.
 536   if (start > this->size_
 537       || (static_cast<unsigned long long>(size)
 538           > static_cast<unsigned long long>(this->size_ - start)))
 539     gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
 540                  "size of file; the file may be corrupt"),
 541                    this->filename().c_str(),
 542                    static_cast<long long>(size),
 543                    static_cast<long long>(start));
 544
 545   unsigned int byteshift;
 546   if (offset == 0)
 547     byteshift = 0;
 548   else
 549     {
 550       unsigned int target_size = (!parameters->target_valid()
 551                                   ? 64
 552                                   : parameters->target().get_size());
 553       byteshift = offset & ((target_size / 8) - 1);
 554
 555       // Set BYTESHIFT to the number of dummy bytes which must be
 556       // inserted before the data in order for this data to be
 557       // aligned.
 558       if (byteshift != 0)
 559         byteshift = (target_size / 8) - byteshift;
 560     }
 561
 562   // If --map-whole-files is set, make sure we have a
 563   // whole file view.  Options may not yet be ready, e.g.,
 564   // when reading a version script.  We then default to
 565   // --no-map-whole-files.
 566   if (this->whole_file_view_ == NULL
 567       && parameters->options_valid()
 568       && parameters->options().map_whole_files())
 569     this->whole_file_view_ = this->make_view(0, this->size_, 0, cache);
 570
 571   // Try to find a View with the required BYTESHIFT.
 572   File_read::View* vshifted;
 573   File_read::View* v = this->find_view(offset + start, size,
 574                                        aligned ? byteshift : -1U,
 575                                        &vshifted);
 576   if (v != NULL)
 577     {
 578       if (cache)
 579         v->set_cache();
 580       return v;
 581     }
 582
 583   // If VSHIFTED is not NULL, then it has the data we need, but with
 584   // the wrong byteshift.
 585   v = vshifted;
 586   if (v != NULL)
 587     {
 588       gold_assert(aligned);
 589
 590       unsigned char* pbytes;
 591       pbytes = static_cast<unsigned char*>(malloc(v->size() + byteshift));
 592       if (pbytes == NULL)
 593         gold_nomem();
 594       memset(pbytes, 0, byteshift);
 595       memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());
 596
 597       File_read::View* shifted_view =
 598           new File_read::View(v->start(), v->size(), pbytes, byteshift,
 599                               cache, View::DATA_ALLOCATED_ARRAY);
 600
 601       this->add_view(shifted_view);
 602       return shifted_view;
 603     }
 604
 605   // Make a new view.  If we don't need an aligned view, use a
 606   // byteshift of 0, so that we can use mmap.
 607   return this->make_view(offset + start, size,
 608                          aligned ? byteshift : 0,
 609                          cache);
 610 }
 611
 612 // Get a view into the file.
 613
 614 const unsigned char*
 615 File_read::get_view(off_t offset, off_t start, section_size_type size,
 616                     bool aligned, bool cache)
 617 {
 618   File_read::View* pv = this->find_or_make_view(offset, start, size,
 619                                                 aligned, cache);
 620   return pv->data() + (offset + start - pv->start() + pv->byteshift());
 621 }
 622
 623 File_view*
 624 File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
 625                             bool aligned, bool cache)
 626 {
 627   File_read::View* pv = this->find_or_make_view(offset, start, size,
 628                                                 aligned, cache);
 629   pv->lock();
 630   return new File_view(*this, pv,
 631                        (pv->data()
 632                         + (offset + start - pv->start() + pv->byteshift())));
 633 }
 634
 635 // Use readv to read COUNT entries from RM starting at START.  BASE
 636 // must be added to all file offsets in RM.
 637
 638 void
 639 File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
 640                     size_t count)
 641 {
 642   unsigned char discard[File_read::page_size];
 643   iovec iov[File_read::max_readv_entries * 2];
 644   size_t iov_index = 0;
 645
 646   off_t first_offset = rm[start].file_offset;
 647   off_t last_offset = first_offset;
 648   ssize_t want = 0;
 649   for (size_t i = 0; i < count; ++i)
 650     {
 651       const Read_multiple_entry& i_entry(rm[start + i]);
 652
 653       if (i_entry.file_offset > last_offset)
 654         {
 655           size_t skip = i_entry.file_offset - last_offset;
 656           gold_assert(skip <= sizeof discard);
 657
 658           iov[iov_index].iov_base = discard;
 659           iov[iov_index].iov_len = skip;
 660           ++iov_index;
 661
 662           want += skip;
 663         }
 664
 665       iov[iov_index].iov_base = i_entry.buffer;
 666       iov[iov_index].iov_len = i_entry.size;
 667       ++iov_index;
 668
 669       want += i_entry.size;
 670
 671       last_offset = i_entry.file_offset + i_entry.size;
 672     }
 673
 674   this->reopen_descriptor();
 675
 676   gold_assert(iov_index < sizeof iov / sizeof iov[0]);
 677
 678   if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
 679     gold_fatal(_("%s: lseek failed: %s"),
 680                this->filename().c_str(), strerror(errno));
 681
 682   ssize_t got = ::readv(this->descriptor_, iov, iov_index);
 683
 684   if (got < 0)
 685     gold_fatal(_("%s: readv failed: %s"),
 686                this->filename().c_str(), strerror(errno));
 687   if (got != want)
 688     gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
 689                this->filename().c_str(),
 690                got, want, static_cast<long long>(base + first_offset));
 691 }
 692
 693 // Portable IOV_MAX.
 694
 695 #if !defined(HAVE_READV)
 696 #define GOLD_IOV_MAX 1
 697 #elif defined(IOV_MAX)
 698 #define GOLD_IOV_MAX IOV_MAX
 699 #else
 700 #define GOLD_IOV_MAX (File_read::max_readv_entries * 2)
 701 #endif
 702
 703 // Read several pieces of data from the file.
 704
 705 void
 706 File_read::read_multiple(off_t base, const Read_multiple& rm)
 707 {
 708   static size_t iov_max = GOLD_IOV_MAX;
 709   size_t count = rm.size();
 710   size_t i = 0;
 711   while (i < count)
 712     {
 713       // Find up to MAX_READV_ENTRIES consecutive entries which are
 714       // less than one page apart.
 715       const Read_multiple_entry& i_entry(rm[i]);
 716       off_t i_off = i_entry.file_offset;
 717       off_t end_off = i_off + i_entry.size;
 718       size_t j;
 719       for (j = i + 1; j < count; ++j)
 720         {
 721           if (j - i >= File_read::max_readv_entries || j - i >= iov_max / 2)
 722             break;
 723           const Read_multiple_entry& j_entry(rm[j]);
 724           off_t j_off = j_entry.file_offset;
 725           gold_assert(j_off >= end_off);
 726           off_t j_end_off = j_off + j_entry.size;
 727           if (j_end_off - end_off >= File_read::page_size)
 728             break;
 729           end_off = j_end_off;
 730         }
 731
 732       if (j == i + 1)
 733         this->read(base + i_off, i_entry.size, i_entry.buffer);
 734       else
 735         {
 736           File_read::View* view = this->find_view(base + i_off,
 737                                                   end_off - i_off,
 738                                                   -1U, NULL);
 739           if (view == NULL)
 740             this->do_readv(base, rm, i, j - i);
 741           else
 742             {
 743               const unsigned char* v = (view->data()
 744                                         + (base + i_off - view->start()
 745                                            + view->byteshift()));
 746               for (size_t k = i; k < j; ++k)
 747                 {
 748                   const Read_multiple_entry& k_entry(rm[k]);
 749                   gold_assert((convert_to_section_size_type(k_entry.file_offset
 750                                                            - i_off)
 751                                + k_entry.size)
 752                               <= convert_to_section_size_type(end_off
 753                                                               - i_off));
 754                   memcpy(k_entry.buffer,
 755                          v + (k_entry.file_offset - i_off),
 756                          k_entry.size);
 757                 }
 758             }
 759         }
 760
 761       i = j;
 762     }
 763 }
 764
 765 // Mark all views as no longer cached.
 766
 767 void
 768 File_read::clear_view_cache_marks()
 769 {
 770   // Just ignore this if there are multiple objects associated with
 771   // the file.  Otherwise we will wind up uncaching and freeing some
 772   // views for other objects.
 773   if (this->object_count_ > 1)
 774     return;
 775
 776   for (Views::iterator p = this->views_.begin();
 777        p != this->views_.end();
 778        ++p)
 779     p->second->clear_cache();
 780   for (Saved_views::iterator p = this->saved_views_.begin();
 781        p != this->saved_views_.end();
 782        ++p)
 783     (*p)->clear_cache();
 784 }
 785
 786 // Remove all the file views.  For a file which has multiple
 787 // associated objects (i.e., an archive), we keep accessed views
 788 // around until next time, in the hopes that they will be useful for
 789 // the next object.
 790
 791 void
 792 File_read::clear_views(Clear_views_mode mode)
 793 {
 794   bool keep_files_mapped = (parameters->options_valid()
 795                             && parameters->options().keep_files_mapped());
 796   Views::iterator p = this->views_.begin();
 797   while (p != this->views_.end())
 798     {
 799       bool should_delete;
 800       if (p->second->is_locked() || p->second->is_permanent_view())
 801         should_delete = false;
 802       else if (mode == CLEAR_VIEWS_ALL)
 803         should_delete = true;
 804       else if ((p->second->should_cache()
 805                 || p->second == this->whole_file_view_)
 806                && keep_files_mapped)
 807         should_delete = false;
 808       else if (this->object_count_ > 1
 809                && p->second->accessed()
 810                && mode != CLEAR_VIEWS_ARCHIVE)
 811         should_delete = false;
 812       else
 813         should_delete = true;
 814
 815       if (should_delete)
 816         {
 817           if (p->second == this->whole_file_view_)
 818             this->whole_file_view_ = NULL;
 819           delete p->second;
 820
 821           // map::erase invalidates only the iterator to the deleted
 822           // element.
 823           Views::iterator pe = p;
 824           ++p;
 825           this->views_.erase(pe);
 826         }
 827       else
 828         {
 829           p->second->clear_accessed();
 830           ++p;
 831         }
 832     }
 833
 834   Saved_views::iterator q = this->saved_views_.begin();
 835   while (q != this->saved_views_.end())
 836     {
 837       if (!(*q)->is_locked())
 838         {
 839           delete *q;
 840           q = this->saved_views_.erase(q);
 841         }
 842       else
 843         {
 844           gold_assert(mode != CLEAR_VIEWS_ALL);
 845           ++q;
 846         }
 847     }
 848 }
 849
 850 // Print statistical information to stderr.  This is used for --stats.
 851
 852 void
 853 File_read::print_stats()
 854 {
 855   fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
 856           program_name, File_read::total_mapped_bytes);
 857   fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
 858           program_name, File_read::maximum_mapped_bytes);
 859 }
 860
 861 // Class File_view.
 862
 863 File_view::~File_view()
 864 {
 865   gold_assert(this->file_.is_locked());
 866   this->view_->unlock();
 867 }
 868
 869 // Class Input_file.
 870
 871 // Create a file given just the filename.
 872
 873 Input_file::Input_file(const char* name)
 874   : found_name_(), file_(), is_in_sysroot_(false), format_(FORMAT_NONE)
 875 {
 876   this->input_argument_ =
 877     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
 878                             "", false, Position_dependent_options());
 879 }
 880
 881 // Create a file for testing.
 882
 883 Input_file::Input_file(const Task* task, const char* name,
 884                        const unsigned char* contents, off_t size)
 885   : file_()
 886 {
 887   this->input_argument_ =
 888     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
 889                             "", false, Position_dependent_options());
 890   bool ok = this->file_.open(task, name, contents, size);
 891   gold_assert(ok);
 892 }
 893
 894 // Return the position dependent options in force for this file.
 895
 896 const Position_dependent_options&
 897 Input_file::options() const
 898 {
 899   return this->input_argument_->options();
 900 }
 901
 902 // Return the name given by the user.  For -lc this will return "c".
 903
 904 const char*
 905 Input_file::name() const
 906 {
 907   return this->input_argument_->name();
 908 }
 909
 910 // Return whether this file is in a system directory.
 911
 912 bool
 913 Input_file::is_in_system_directory() const
 914 {
 915   if (this->is_in_sysroot())
 916     return true;
 917   return parameters->options().is_in_system_directory(this->filename());
 918 }
 919
 920 // Return whether we are only reading symbols.
 921
 922 bool
 923 Input_file::just_symbols() const
 924 {
 925   return this->input_argument_->just_symbols();
 926 }
 927
 928 // Return whether this is a file that we will search for in the list
 929 // of directories.
 930
 931 bool
 932 Input_file::will_search_for() const
 933 {
 934   return (!IS_ABSOLUTE_PATH(this->input_argument_->name())
 935           && (this->input_argument_->is_lib()
 936               || this->input_argument_->is_searched_file()
 937               || this->input_argument_->extra_search_path() != NULL));
 938 }
 939
 940 // Return the file last modification time.  Calls gold_fatal if the stat
 941 // system call failed.
 942
 943 Timespec
 944 File_read::get_mtime()
 945 {
 946   struct stat file_stat;
 947   this->reopen_descriptor();
 948
 949   if (fstat(this->descriptor_, &file_stat) < 0)
 950     gold_fatal(_("%s: stat failed: %s"), this->name_.c_str(),
 951                strerror(errno));
 952 #ifdef HAVE_STAT_ST_MTIM
 953   return Timespec(file_stat.st_mtim.tv_sec, file_stat.st_mtim.tv_nsec);
 954 #else
 955   return Timespec(file_stat.st_mtime, 0);
 956 #endif
 957 }
 958
 959 // Try to find a file in the extra search dirs.  Returns true on success.
 960
 961 bool
 962 Input_file::try_extra_search_path(int* pindex,
 963                                   const Input_file_argument* input_argument,
 964                                   std::string filename, std::string* found_name,
 965                                   std::string* namep)
 966 {
 967   if (input_argument->extra_search_path() == NULL)
 968     return false;
 969
 970   std::string name = input_argument->extra_search_path();
 971   if (!IS_DIR_SEPARATOR(name[name.length() - 1]))
 972     name += '/';
 973   name += filename;
 974
 975   struct stat dummy_stat;
 976   if (*pindex > 0 || ::stat(name.c_str(), &dummy_stat) < 0)
 977     return false;
 978
 979   *found_name = filename;
 980   *namep = name;
 981   return true;
 982 }
 983
 984 // Find the actual file.
 985 // If the filename is not absolute, we assume it is in the current
 986 // directory *except* when:
 987 //    A) input_argument_->is_lib() is true;
 988 //    B) input_argument_->is_searched_file() is true; or
 989 //    C) input_argument_->extra_search_path() is not empty.
 990 // In each, we look in extra_search_path + library_path to find
 991 // the file location, rather than the current directory.
 992
 993 bool
 994 Input_file::find_file(const Dirsearch& dirpath, int* pindex,
 995                       const Input_file_argument* input_argument,
 996                       bool* is_in_sysroot,
 997                       std::string* found_name, std::string* namep)
 998 {
 999   std::string name;
1000
1001   // Case 1: name is an absolute file, just try to open it
1002   // Case 2: name is relative but is_lib is false, is_searched_file is false,
1003   //         and extra_search_path is empty
1004   if (IS_ABSOLUTE_PATH(input_argument->name())
1005       || (!input_argument->is_lib()
1006           && !input_argument->is_searched_file()
1007           && input_argument->extra_search_path() == NULL))
1008     {
1009       name = input_argument->name();
1010       *found_name = name;
1011       *namep = name;
1012       return true;
1013     }
1014   // Case 3: is_lib is true or is_searched_file is true
1015   else if (input_argument->is_lib()
1016            || input_argument->is_searched_file())
1017     {
1018       std::vector<std::string> names;
1019       names.reserve(2);
1020       if (input_argument->is_lib())
1021         {
1022           std::string prefix = "lib";
1023           prefix += input_argument->name();
1024           if (parameters->options().is_static()
1025               || !input_argument->options().Bdynamic())
1026             names.push_back(prefix + ".a");
1027           else
1028             {
1029               names.push_back(prefix + ".so");
1030               names.push_back(prefix + ".a");
1031             }
1032         }
1033       else
1034         names.push_back(input_argument->name());
1035
1036       for (std::vector<std::string>::const_iterator n = names.begin();
1037            n != names.end();
1038            ++n)
1039         if (Input_file::try_extra_search_path(pindex, input_argument, *n,
1040                                               found_name, namep))
1041           return true;
1042
1043       // It is not in the extra_search_path.
1044       name = dirpath.find(names, is_in_sysroot, pindex, found_name);
1045       if (name.empty())
1046         {
1047           gold_error(_("cannot find %s%s"),
1048                      input_argument->is_lib() ? "-l" : "",
1049                      input_argument->name());
1050           return false;
1051         }
1052       *namep = name;
1053       return true;
1054     }
1055   // Case 4: extra_search_path is not empty
1056   else
1057     {
1058       gold_assert(input_argument->extra_search_path() != NULL);
1059
1060       if (try_extra_search_path(pindex, input_argument, input_argument->name(),
1061                                 found_name, namep))
1062         return true;
1063
1064       // extra_search_path failed, so check the normal search-path.
1065       int index = *pindex;
1066       if (index > 0)
1067         --index;
1068       name = dirpath.find(std::vector<std::string>(1, input_argument->name()),
1069                           is_in_sysroot, &index, found_name);
1070       if (name.empty())
1071         {
1072           gold_error(_("cannot find %s"),
1073                      input_argument->name());
1074           return false;
1075         }
1076       *namep = name;
1077       *pindex = index + 1;
1078       return true;
1079     }
1080 }
1081
1082 // Open the file.
1083
1084 bool
1085 Input_file::open(const Dirsearch& dirpath, const Task* task, int* pindex)
1086 {
1087   std::string name;
1088   if (!Input_file::find_file(dirpath, pindex, this->input_argument_,
1089                              &this->is_in_sysroot_, &this->found_name_, &name))
1090     return false;
1091
1092   // Now that we've figured out where the file lives, try to open it.
1093
1094   General_options::Object_format format =
1095     this->input_argument_->options().format_enum();
1096   bool ok;
1097   if (format == General_options::OBJECT_FORMAT_ELF)
1098     {
1099       ok = this->file_.open(task, name);
1100       this->format_ = FORMAT_ELF;
1101     }
1102   else
1103     {
1104       gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
1105       ok = this->open_binary(task, name);
1106       this->format_ = FORMAT_BINARY;
1107     }
1108
1109   if (!ok)
1110     {
1111       gold_error(_("cannot open %s: %s"),
1112                  name.c_str(), strerror(errno));
1113       this->format_ = FORMAT_NONE;
1114       return false;
1115     }
1116
1117   return true;
1118 }
1119
1120 // Open a file for --format binary.
1121
1122 bool
1123 Input_file::open_binary(const Task* task, const std::string& name)
1124 {
1125   // In order to open a binary file, we need machine code, size, and
1126   // endianness.  We may not have a valid target at this point, in
1127   // which case we use the default target.
1128   parameters_force_valid_target();
1129   const Target& target(parameters->target());
1130
1131   Binary_to_elf binary_to_elf(target.machine_code(),
1132                               target.get_size(),
1133                               target.is_big_endian(),
1134                               name);
1135   if (!binary_to_elf.convert(task))
1136     return false;
1137   return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
1138                           binary_to_elf.converted_size());
1139 }
1140
1141 } // End namespace gold.