gold/fileread.cc

   1 // fileread.cc -- read files for gold
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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   this->token_.add_writer(task);
 297   this->released_ = false;
 298 }
 299
 300 // Unlock the file.
 301
 302 void
 303 File_read::unlock(const Task* task)
 304 {
 305   this->release();
 306   this->token_.remove_writer(task);
 307 }
 308
 309 // Return whether the file is locked.
 310
 311 bool
 312 File_read::is_locked() const
 313 {
 314   if (!this->token_.is_writable())
 315     return true;
 316   // The file is not locked, so it should have been released.
 317   gold_assert(this->released_);
 318   return false;
 319 }
 320
 321 // See if we have a view which covers the file starting at START for
 322 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
 323 // If BYTESHIFT is not -1U, the returned View must have the specified
 324 // byte shift; otherwise, it may have any byte shift.  If VSHIFTED is
 325 // not NULL, this sets *VSHIFTED to a view which would have worked if
 326 // not for the requested BYTESHIFT.
 327
 328 inline File_read::View*
 329 File_read::find_view(off_t start, section_size_type size,
 330                      unsigned int byteshift, File_read::View** vshifted) const
 331 {
 332   if (vshifted != NULL)
 333     *vshifted = NULL;
 334
 335   // If we have the whole file mmapped, and the alignment is right,
 336   // we can return it.
 337   if (this->whole_file_view_)
 338     if (byteshift == -1U || byteshift == 0)
 339       return this->whole_file_view_;
 340
 341   off_t page = File_read::page_offset(start);
 342
 343   unsigned int bszero = 0;
 344   Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
 345                                                                     bszero));
 346
 347   while (p != this->views_.end() && p->first.first <= page)
 348     {
 349       if (p->second->start() <= start
 350           && (p->second->start() + static_cast<off_t>(p->second->size())
 351               >= start + static_cast<off_t>(size)))
 352         {
 353           if (byteshift == -1U || byteshift == p->second->byteshift())
 354             {
 355               p->second->set_accessed();
 356               return p->second;
 357             }
 358
 359           if (vshifted != NULL && *vshifted == NULL)
 360             *vshifted = p->second;
 361         }
 362
 363       ++p;
 364     }
 365
 366   return NULL;
 367 }
 368
 369 // Read SIZE bytes from the file starting at offset START.  Read into
 370 // the buffer at P.
 371
 372 void
 373 File_read::do_read(off_t start, section_size_type size, void* p)
 374 {
 375   ssize_t bytes;
 376   if (this->whole_file_view_ != NULL)
 377     {
 378       bytes = this->size_ - start;
 379       if (static_cast<section_size_type>(bytes) >= size)
 380         {
 381           memcpy(p, this->whole_file_view_->data() + start, size);
 382           return;
 383         }
 384     }
 385   else
 386     {
 387       this->reopen_descriptor();
 388       bytes = ::pread(this->descriptor_, p, size, start);
 389       if (static_cast<section_size_type>(bytes) == size)
 390         return;
 391
 392       if (bytes < 0)
 393         {
 394           gold_fatal(_("%s: pread failed: %s"),
 395                      this->filename().c_str(), strerror(errno));
 396           return;
 397         }
 398     }
 399
 400   gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
 401              this->filename().c_str(),
 402              static_cast<long long>(bytes),
 403              static_cast<long long>(size),
 404              static_cast<long long>(start));
 405 }
 406
 407 // Read data from the file.
 408
 409 void
 410 File_read::read(off_t start, section_size_type size, void* p)
 411 {
 412   const File_read::View* pv = this->find_view(start, size, -1U, NULL);
 413   if (pv != NULL)
 414     {
 415       memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
 416       return;
 417     }
 418
 419   this->do_read(start, size, p);
 420 }
 421
 422 // Add a new view.  There may already be an existing view at this
 423 // offset.  If there is, the new view will be larger, and should
 424 // replace the old view.
 425
 426 void
 427 File_read::add_view(File_read::View* v)
 428 {
 429   std::pair<Views::iterator, bool> ins =
 430     this->views_.insert(std::make_pair(std::make_pair(v->start(),
 431                                                       v->byteshift()),
 432                                        v));
 433   if (ins.second)
 434     return;
 435
 436   // There was an existing view at this offset.  It must not be large
 437   // enough.  We can't delete it here, since something might be using
 438   // it; we put it on a list to be deleted when the file is unlocked.
 439   File_read::View* vold = ins.first->second;
 440   gold_assert(vold->size() < v->size());
 441   if (vold->should_cache())
 442     {
 443       v->set_cache();
 444       vold->clear_cache();
 445     }
 446   this->saved_views_.push_back(vold);
 447
 448   ins.first->second = v;
 449 }
 450
 451 // Make a new view with a specified byteshift, reading the data from
 452 // the file.
 453
 454 File_read::View*
 455 File_read::make_view(off_t start, section_size_type size,
 456                      unsigned int byteshift, bool cache)
 457 {
 458   gold_assert(size > 0);
 459
 460   // Check that start and end of the view are within the file.
 461   if (start > this->size_
 462       || (static_cast<unsigned long long>(size)
 463           > static_cast<unsigned long long>(this->size_ - start)))
 464     gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
 465                  "size of file; the file may be corrupt"),
 466                    this->filename().c_str(),
 467                    static_cast<long long>(size),
 468                    static_cast<long long>(start));
 469
 470   off_t poff = File_read::page_offset(start);
 471
 472   section_size_type psize = File_read::pages(size + (start - poff));
 473
 474   if (poff + static_cast<off_t>(psize) >= this->size_)
 475     {
 476       psize = this->size_ - poff;
 477       gold_assert(psize >= size);
 478     }
 479
 480   void* p;
 481   View::Data_ownership ownership;
 482   if (byteshift != 0)
 483     {
 484       p = malloc(psize + byteshift);
 485       if (p == NULL)
 486         gold_nomem();
 487       memset(p, 0, byteshift);
 488       this->do_read(poff, psize, static_cast<unsigned char*>(p) + byteshift);
 489       ownership = View::DATA_ALLOCATED_ARRAY;
 490     }
 491   else
 492     {
 493       this->reopen_descriptor();
 494       p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE, this->descriptor_, poff);
 495       if (p != MAP_FAILED)
 496         {
 497           ownership = View::DATA_MMAPPED;
 498           this->mapped_bytes_ += psize;
 499         }
 500       else
 501         {
 502           p = malloc(psize);
 503           if (p == NULL)
 504             gold_nomem();
 505           this->do_read(poff, psize, p);
 506           ownership = View::DATA_ALLOCATED_ARRAY;
 507         }
 508     }
 509
 510   const unsigned char* pbytes = static_cast<const unsigned char*>(p);
 511   File_read::View* v = new File_read::View(poff, psize, pbytes, byteshift,
 512                                            cache, ownership);
 513
 514   this->add_view(v);
 515
 516   return v;
 517 }
 518
 519 // Find a View or make a new one, shifted as required by the file
 520 // offset OFFSET and ALIGNED.
 521
 522 File_read::View*
 523 File_read::find_or_make_view(off_t offset, off_t start,
 524                              section_size_type size, bool aligned, bool cache)
 525 {
 526   unsigned int byteshift;
 527   if (offset == 0)
 528     byteshift = 0;
 529   else
 530     {
 531       unsigned int target_size = (!parameters->target_valid()
 532                                   ? 64
 533                                   : parameters->target().get_size());
 534       byteshift = offset & ((target_size / 8) - 1);
 535
 536       // Set BYTESHIFT to the number of dummy bytes which must be
 537       // inserted before the data in order for this data to be
 538       // aligned.
 539       if (byteshift != 0)
 540         byteshift = (target_size / 8) - byteshift;
 541     }
 542
 543   // If --map-whole-files is set, make sure we have a
 544   // whole file view.  Options may not yet be ready, e.g.,
 545   // when reading a version script.  We then default to
 546   // --no-map-whole-files.
 547   if (this->whole_file_view_ == NULL
 548       && parameters->options_valid()
 549       && parameters->options().map_whole_files())
 550     this->whole_file_view_ = this->make_view(0, this->size_, 0, cache);
 551
 552   // Try to find a View with the required BYTESHIFT.
 553   File_read::View* vshifted;
 554   File_read::View* v = this->find_view(offset + start, size,
 555                                        aligned ? byteshift : -1U,
 556                                        &vshifted);
 557   if (v != NULL)
 558     {
 559       if (cache)
 560         v->set_cache();
 561       return v;
 562     }
 563
 564   // If VSHIFTED is not NULL, then it has the data we need, but with
 565   // the wrong byteshift.
 566   v = vshifted;
 567   if (v != NULL)
 568     {
 569       gold_assert(aligned);
 570
 571       unsigned char* pbytes;
 572       pbytes = static_cast<unsigned char*>(malloc(v->size() + byteshift));
 573       if (pbytes == NULL)
 574         gold_nomem();
 575       memset(pbytes, 0, byteshift);
 576       memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());
 577
 578       File_read::View* shifted_view =
 579           new File_read::View(v->start(), v->size(), pbytes, byteshift,
 580                               cache, View::DATA_ALLOCATED_ARRAY);
 581
 582       this->add_view(shifted_view);
 583       return shifted_view;
 584     }
 585
 586   // Make a new view.  If we don't need an aligned view, use a
 587   // byteshift of 0, so that we can use mmap.
 588   return this->make_view(offset + start, size,
 589                          aligned ? byteshift : 0,
 590                          cache);
 591 }
 592
 593 // Get a view into the file.
 594
 595 const unsigned char*
 596 File_read::get_view(off_t offset, off_t start, section_size_type size,
 597                     bool aligned, bool cache)
 598 {
 599   File_read::View* pv = this->find_or_make_view(offset, start, size,
 600                                                 aligned, cache);
 601   return pv->data() + (offset + start - pv->start() + pv->byteshift());
 602 }
 603
 604 File_view*
 605 File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
 606                             bool aligned, bool cache)
 607 {
 608   File_read::View* pv = this->find_or_make_view(offset, start, size,
 609                                                 aligned, cache);
 610   pv->lock();
 611   return new File_view(*this, pv,
 612                        (pv->data()
 613                         + (offset + start - pv->start() + pv->byteshift())));
 614 }
 615
 616 // Use readv to read COUNT entries from RM starting at START.  BASE
 617 // must be added to all file offsets in RM.
 618
 619 void
 620 File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
 621                     size_t count)
 622 {
 623   unsigned char discard[File_read::page_size];
 624   iovec iov[File_read::max_readv_entries * 2];
 625   size_t iov_index = 0;
 626
 627   off_t first_offset = rm[start].file_offset;
 628   off_t last_offset = first_offset;
 629   ssize_t want = 0;
 630   for (size_t i = 0; i < count; ++i)
 631     {
 632       const Read_multiple_entry& i_entry(rm[start + i]);
 633
 634       if (i_entry.file_offset > last_offset)
 635         {
 636           size_t skip = i_entry.file_offset - last_offset;
 637           gold_assert(skip <= sizeof discard);
 638
 639           iov[iov_index].iov_base = discard;
 640           iov[iov_index].iov_len = skip;
 641           ++iov_index;
 642
 643           want += skip;
 644         }
 645
 646       iov[iov_index].iov_base = i_entry.buffer;
 647       iov[iov_index].iov_len = i_entry.size;
 648       ++iov_index;
 649
 650       want += i_entry.size;
 651
 652       last_offset = i_entry.file_offset + i_entry.size;
 653     }
 654
 655   this->reopen_descriptor();
 656
 657   gold_assert(iov_index < sizeof iov / sizeof iov[0]);
 658
 659   if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
 660     gold_fatal(_("%s: lseek failed: %s"),
 661                this->filename().c_str(), strerror(errno));
 662
 663   ssize_t got = ::readv(this->descriptor_, iov, iov_index);
 664
 665   if (got < 0)
 666     gold_fatal(_("%s: readv failed: %s"),
 667                this->filename().c_str(), strerror(errno));
 668   if (got != want)
 669     gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
 670                this->filename().c_str(),
 671                got, want, static_cast<long long>(base + first_offset));
 672 }
 673
 674 // Portable IOV_MAX.
 675
 676 #if !defined(HAVE_READV)
 677 #define GOLD_IOV_MAX 1
 678 #elif defined(IOV_MAX)
 679 #define GOLD_IOV_MAX IOV_MAX
 680 #else
 681 #define GOLD_IOV_MAX (File_read::max_readv_entries * 2)
 682 #endif
 683
 684 // Read several pieces of data from the file.
 685
 686 void
 687 File_read::read_multiple(off_t base, const Read_multiple& rm)
 688 {
 689   static size_t iov_max = GOLD_IOV_MAX;
 690   size_t count = rm.size();
 691   size_t i = 0;
 692   while (i < count)
 693     {
 694       // Find up to MAX_READV_ENTRIES consecutive entries which are
 695       // less than one page apart.
 696       const Read_multiple_entry& i_entry(rm[i]);
 697       off_t i_off = i_entry.file_offset;
 698       off_t end_off = i_off + i_entry.size;
 699       size_t j;
 700       for (j = i + 1; j < count; ++j)
 701         {
 702           if (j - i >= File_read::max_readv_entries || j - i >= iov_max / 2)
 703             break;
 704           const Read_multiple_entry& j_entry(rm[j]);
 705           off_t j_off = j_entry.file_offset;
 706           gold_assert(j_off >= end_off);
 707           off_t j_end_off = j_off + j_entry.size;
 708           if (j_end_off - end_off >= File_read::page_size)
 709             break;
 710           end_off = j_end_off;
 711         }
 712
 713       if (j == i + 1)
 714         this->read(base + i_off, i_entry.size, i_entry.buffer);
 715       else
 716         {
 717           File_read::View* view = this->find_view(base + i_off,
 718                                                   end_off - i_off,
 719                                                   -1U, NULL);
 720           if (view == NULL)
 721             this->do_readv(base, rm, i, j - i);
 722           else
 723             {
 724               const unsigned char* v = (view->data()
 725                                         + (base + i_off - view->start()
 726                                            + view->byteshift()));
 727               for (size_t k = i; k < j; ++k)
 728                 {
 729                   const Read_multiple_entry& k_entry(rm[k]);
 730                   gold_assert((convert_to_section_size_type(k_entry.file_offset
 731                                                            - i_off)
 732                                + k_entry.size)
 733                               <= convert_to_section_size_type(end_off
 734                                                               - i_off));
 735                   memcpy(k_entry.buffer,
 736                          v + (k_entry.file_offset - i_off),
 737                          k_entry.size);
 738                 }
 739             }
 740         }
 741
 742       i = j;
 743     }
 744 }
 745
 746 // Mark all views as no longer cached.
 747
 748 void
 749 File_read::clear_view_cache_marks()
 750 {
 751   // Just ignore this if there are multiple objects associated with
 752   // the file.  Otherwise we will wind up uncaching and freeing some
 753   // views for other objects.
 754   if (this->object_count_ > 1)
 755     return;
 756
 757   for (Views::iterator p = this->views_.begin();
 758        p != this->views_.end();
 759        ++p)
 760     p->second->clear_cache();
 761   for (Saved_views::iterator p = this->saved_views_.begin();
 762        p != this->saved_views_.end();
 763        ++p)
 764     (*p)->clear_cache();
 765 }
 766
 767 // Remove all the file views.  For a file which has multiple
 768 // associated objects (i.e., an archive), we keep accessed views
 769 // around until next time, in the hopes that they will be useful for
 770 // the next object.
 771
 772 void
 773 File_read::clear_views(Clear_views_mode mode)
 774 {
 775   bool keep_files_mapped = (parameters->options_valid()
 776                             && parameters->options().keep_files_mapped());
 777   Views::iterator p = this->views_.begin();
 778   while (p != this->views_.end())
 779     {
 780       bool should_delete;
 781       if (p->second->is_locked() || p->second->is_permanent_view())
 782         should_delete = false;
 783       else if (mode == CLEAR_VIEWS_ALL)
 784         should_delete = true;
 785       else if ((p->second->should_cache()
 786                 || p->second == this->whole_file_view_)
 787                && keep_files_mapped)
 788         should_delete = false;
 789       else if (this->object_count_ > 1
 790                && p->second->accessed()
 791                && mode != CLEAR_VIEWS_ARCHIVE)
 792         should_delete = false;
 793       else
 794         should_delete = true;
 795
 796       if (should_delete)
 797         {
 798           if (p->second == this->whole_file_view_)
 799             this->whole_file_view_ = NULL;
 800           delete p->second;
 801
 802           // map::erase invalidates only the iterator to the deleted
 803           // element.
 804           Views::iterator pe = p;
 805           ++p;
 806           this->views_.erase(pe);
 807         }
 808       else
 809         {
 810           p->second->clear_accessed();
 811           ++p;
 812         }
 813     }
 814
 815   Saved_views::iterator q = this->saved_views_.begin();
 816   while (q != this->saved_views_.end())
 817     {
 818       if (!(*q)->is_locked())
 819         {
 820           delete *q;
 821           q = this->saved_views_.erase(q);
 822         }
 823       else
 824         {
 825           gold_assert(mode != CLEAR_VIEWS_ALL);
 826           ++q;
 827         }
 828     }
 829 }
 830
 831 // Print statistical information to stderr.  This is used for --stats.
 832
 833 void
 834 File_read::print_stats()
 835 {
 836   fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
 837           program_name, File_read::total_mapped_bytes);
 838   fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
 839           program_name, File_read::maximum_mapped_bytes);
 840 }
 841
 842 // Class File_view.
 843
 844 File_view::~File_view()
 845 {
 846   gold_assert(this->file_.is_locked());
 847   this->view_->unlock();
 848 }
 849
 850 // Class Input_file.
 851
 852 // Create a file for testing.
 853
 854 Input_file::Input_file(const Task* task, const char* name,
 855                        const unsigned char* contents, off_t size)
 856   : file_()
 857 {
 858   this->input_argument_ =
 859     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
 860                             "", false, Position_dependent_options());
 861   bool ok = this->file_.open(task, name, contents, size);
 862   gold_assert(ok);
 863 }
 864
 865 // Return the position dependent options in force for this file.
 866
 867 const Position_dependent_options&
 868 Input_file::options() const
 869 {
 870   return this->input_argument_->options();
 871 }
 872
 873 // Return the name given by the user.  For -lc this will return "c".
 874
 875 const char*
 876 Input_file::name() const
 877 {
 878   return this->input_argument_->name();
 879 }
 880
 881 // Return whether this file is in a system directory.
 882
 883 bool
 884 Input_file::is_in_system_directory() const
 885 {
 886   if (this->is_in_sysroot())
 887     return true;
 888   return parameters->options().is_in_system_directory(this->filename());
 889 }
 890
 891 // Return whether we are only reading symbols.
 892
 893 bool
 894 Input_file::just_symbols() const
 895 {
 896   return this->input_argument_->just_symbols();
 897 }
 898
 899 // Return whether this is a file that we will search for in the list
 900 // of directories.
 901
 902 bool
 903 Input_file::will_search_for() const
 904 {
 905   return (!IS_ABSOLUTE_PATH(this->input_argument_->name())
 906           && (this->input_argument_->is_lib()
 907               || this->input_argument_->is_searched_file()
 908               || this->input_argument_->extra_search_path() != NULL));
 909 }
 910
 911 // Return the file last modification time.  Calls gold_fatal if the stat
 912 // system call failed.
 913
 914 Timespec
 915 File_read::get_mtime()
 916 {
 917   struct stat file_stat;
 918   this->reopen_descriptor();
 919
 920   if (fstat(this->descriptor_, &file_stat) < 0)
 921     gold_fatal(_("%s: stat failed: %s"), this->name_.c_str(),
 922                strerror(errno));
 923 #ifdef HAVE_STAT_ST_MTIM
 924   return Timespec(file_stat.st_mtim.tv_sec, file_stat.st_mtim.tv_nsec);
 925 #else
 926   return Timespec(file_stat.st_mtime, 0);
 927 #endif
 928 }
 929
 930 // Try to find a file in the extra search dirs.  Returns true on success.
 931
 932 bool
 933 Input_file::try_extra_search_path(int* pindex,
 934                                   const Input_file_argument* input_argument,
 935                                   std::string filename, std::string* found_name,
 936                                   std::string* namep)
 937 {
 938   if (input_argument->extra_search_path() == NULL)
 939     return false;
 940
 941   std::string name = input_argument->extra_search_path();
 942   if (!IS_DIR_SEPARATOR(name[name.length() - 1]))
 943     name += '/';
 944   name += filename;
 945
 946   struct stat dummy_stat;
 947   if (*pindex > 0 || ::stat(name.c_str(), &dummy_stat) < 0)
 948     return false;
 949
 950   *found_name = filename;
 951   *namep = name;
 952   return true;
 953 }
 954
 955 // Find the actual file.
 956 // If the filename is not absolute, we assume it is in the current
 957 // directory *except* when:
 958 //    A) input_argument_->is_lib() is true;
 959 //    B) input_argument_->is_searched_file() is true; or
 960 //    C) input_argument_->extra_search_path() is not empty.
 961 // In each, we look in extra_search_path + library_path to find
 962 // the file location, rather than the current directory.
 963
 964 bool
 965 Input_file::find_file(const Dirsearch& dirpath, int* pindex,
 966                       const Input_file_argument* input_argument,
 967                       bool* is_in_sysroot,
 968                       std::string* found_name, std::string* namep)
 969 {
 970   std::string name;
 971
 972   // Case 1: name is an absolute file, just try to open it
 973   // Case 2: name is relative but is_lib is false, is_searched_file is false,
 974   //         and extra_search_path is empty
 975   if (IS_ABSOLUTE_PATH(input_argument->name())
 976       || (!input_argument->is_lib()
 977           && !input_argument->is_searched_file()
 978           && input_argument->extra_search_path() == NULL))
 979     {
 980       name = input_argument->name();
 981       *found_name = name;
 982       *namep = name;
 983       return true;
 984     }
 985   // Case 3: is_lib is true or is_searched_file is true
 986   else if (input_argument->is_lib()
 987            || input_argument->is_searched_file())
 988     {
 989       std::vector<std::string> names;
 990       names.reserve(2);
 991       if (input_argument->is_lib())
 992         {
 993           std::string prefix = "lib";
 994           prefix += input_argument->name();
 995           if (parameters->options().is_static()
 996               || !input_argument->options().Bdynamic())
 997             names.push_back(prefix + ".a");
 998           else
 999             {
1000               names.push_back(prefix + ".so");
1001               names.push_back(prefix + ".a");
1002             }
1003         }
1004       else
1005         names.push_back(input_argument->name());
1006
1007       for (std::vector<std::string>::const_iterator n = names.begin();
1008            n != names.end();
1009            ++n)
1010         if (Input_file::try_extra_search_path(pindex, input_argument, *n,
1011                                               found_name, namep))
1012           return true;
1013
1014       // It is not in the extra_search_path.
1015       name = dirpath.find(names, is_in_sysroot, pindex, found_name);
1016       if (name.empty())
1017         {
1018           gold_error(_("cannot find %s%s"),
1019                      input_argument->is_lib() ? "-l" : "",
1020                      input_argument->name());
1021           return false;
1022         }
1023       *namep = name;
1024       return true;
1025     }
1026   // Case 4: extra_search_path is not empty
1027   else
1028     {
1029       gold_assert(input_argument->extra_search_path() != NULL);
1030
1031       if (try_extra_search_path(pindex, input_argument, input_argument->name(),
1032                                 found_name, namep))
1033         return true;
1034
1035       // extra_search_path failed, so check the normal search-path.
1036       int index = *pindex;
1037       if (index > 0)
1038         --index;
1039       name = dirpath.find(std::vector<std::string>(1, input_argument->name()),
1040                           is_in_sysroot, &index, found_name);
1041       if (name.empty())
1042         {
1043           gold_error(_("cannot find %s"),
1044                      input_argument->name());
1045           return false;
1046         }
1047       *namep = name;
1048       *pindex = index + 1;
1049       return true;
1050     }
1051 }
1052
1053 // Open the file.
1054
1055 bool
1056 Input_file::open(const Dirsearch& dirpath, const Task* task, int* pindex)
1057 {
1058   std::string name;
1059   if (!Input_file::find_file(dirpath, pindex, this->input_argument_,
1060                              &this->is_in_sysroot_, &this->found_name_, &name))
1061     return false;
1062
1063   // Now that we've figured out where the file lives, try to open it.
1064
1065   General_options::Object_format format =
1066     this->input_argument_->options().format_enum();
1067   bool ok;
1068   if (format == General_options::OBJECT_FORMAT_ELF)
1069     {
1070       ok = this->file_.open(task, name);
1071       this->format_ = FORMAT_ELF;
1072     }
1073   else
1074     {
1075       gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
1076       ok = this->open_binary(task, name);
1077       this->format_ = FORMAT_BINARY;
1078     }
1079
1080   if (!ok)
1081     {
1082       gold_error(_("cannot open %s: %s"),
1083                  name.c_str(), strerror(errno));
1084       this->format_ = FORMAT_NONE;
1085       return false;
1086     }
1087
1088   return true;
1089 }
1090
1091 // Open a file for --format binary.
1092
1093 bool
1094 Input_file::open_binary(const Task* task, const std::string& name)
1095 {
1096   // In order to open a binary file, we need machine code, size, and
1097   // endianness.  We may not have a valid target at this point, in
1098   // which case we use the default target.
1099   parameters_force_valid_target();
1100   const Target& target(parameters->target());
1101
1102   Binary_to_elf binary_to_elf(target.machine_code(),
1103                               target.get_size(),
1104                               target.is_big_endian(),
1105                               name);
1106   if (!binary_to_elf.convert(task))
1107     return false;
1108   return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
1109                           binary_to_elf.converted_size());
1110 }
1111
1112 } // End namespace gold.