gold/fileread.cc

   1 // fileread.cc -- read files for gold
   2
   3 // Copyright 2006, 2007, 2008, 2009 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 <fcntl.h>
  28 #include <unistd.h>
  29 #include <sys/mman.h>
  30 #include <sys/uio.h>
  31 #include <sys/stat.h>
  32 #include "filenames.h"
  33
  34 #include "debug.h"
  35 #include "parameters.h"
  36 #include "options.h"
  37 #include "dirsearch.h"
  38 #include "target.h"
  39 #include "binary.h"
  40 #include "descriptors.h"
  41 #include "fileread.h"
  42
  43 #ifndef HAVE_READV
  44 struct iovec { void* iov_base; size_t iov_len };
  45 ssize_t
  46 readv(int, const iovec*, int)
  47 {
  48   gold_unreachable();
  49 }
  50 #endif
  51
  52 namespace gold
  53 {
  54
  55 // Class File_read::View.
  56
  57 File_read::View::~View()
  58 {
  59   gold_assert(!this->is_locked());
  60   if (!this->mapped_)
  61     delete[] this->data_;
  62   else
  63     {
  64       if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
  65         gold_warning(_("munmap failed: %s"), strerror(errno));
  66
  67       File_read::current_mapped_bytes -= this->size_;
  68     }
  69 }
  70
  71 void
  72 File_read::View::lock()
  73 {
  74   ++this->lock_count_;
  75 }
  76
  77 void
  78 File_read::View::unlock()
  79 {
  80   gold_assert(this->lock_count_ > 0);
  81   --this->lock_count_;
  82 }
  83
  84 bool
  85 File_read::View::is_locked()
  86 {
  87   return this->lock_count_ > 0;
  88 }
  89
  90 // Class File_read.
  91
  92 // The File_read static variables.
  93 unsigned long long File_read::total_mapped_bytes;
  94 unsigned long long File_read::current_mapped_bytes;
  95 unsigned long long File_read::maximum_mapped_bytes;
  96
  97 File_read::~File_read()
  98 {
  99   gold_assert(this->token_.is_writable());
 100   if (this->is_descriptor_opened_)
 101     {
 102       release_descriptor(this->descriptor_, true);
 103       this->descriptor_ = -1;
 104       this->is_descriptor_opened_ = false;
 105     }
 106   this->name_.clear();
 107   this->clear_views(true);
 108 }
 109
 110 // Open the file.
 111
 112 bool
 113 File_read::open(const Task* task, const std::string& name)
 114 {
 115   gold_assert(this->token_.is_writable()
 116               && this->descriptor_ < 0
 117               && !this->is_descriptor_opened_
 118               && this->name_.empty());
 119   this->name_ = name;
 120
 121   this->descriptor_ = open_descriptor(-1, this->name_.c_str(),
 122                                       O_RDONLY);
 123
 124   if (this->descriptor_ >= 0)
 125     {
 126       this->is_descriptor_opened_ = true;
 127       struct stat s;
 128       if (::fstat(this->descriptor_, &s) < 0)
 129         gold_error(_("%s: fstat failed: %s"),
 130                    this->name_.c_str(), strerror(errno));
 131       this->size_ = s.st_size;
 132       gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
 133                  this->name_.c_str());
 134
 135       this->token_.add_writer(task);
 136     }
 137
 138   return this->descriptor_ >= 0;
 139 }
 140
 141 // Open the file with the contents in memory.
 142
 143 bool
 144 File_read::open(const Task* task, const std::string& name,
 145                 const unsigned char* contents, off_t size)
 146 {
 147   gold_assert(this->token_.is_writable()
 148               && this->descriptor_ < 0
 149               && !this->is_descriptor_opened_
 150               && this->name_.empty());
 151   this->name_ = name;
 152   this->contents_ = contents;
 153   this->size_ = size;
 154   this->token_.add_writer(task);
 155   return true;
 156 }
 157
 158 // Reopen a descriptor if necessary.
 159
 160 void
 161 File_read::reopen_descriptor()
 162 {
 163   if (!this->is_descriptor_opened_)
 164     {
 165       this->descriptor_ = open_descriptor(this->descriptor_,
 166                                           this->name_.c_str(),
 167                                           O_RDONLY);
 168       if (this->descriptor_ < 0)
 169         gold_fatal(_("could not reopen file %s"), this->name_.c_str());
 170       this->is_descriptor_opened_ = true;
 171     }
 172 }
 173
 174 // Release the file.  This is called when we are done with the file in
 175 // a Task.
 176
 177 void
 178 File_read::release()
 179 {
 180   gold_assert(this->is_locked());
 181
 182   File_read::total_mapped_bytes += this->mapped_bytes_;
 183   File_read::current_mapped_bytes += this->mapped_bytes_;
 184   this->mapped_bytes_ = 0;
 185   if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
 186     File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
 187
 188   // Only clear views if there is only one attached object.  Otherwise
 189   // we waste time trying to clear cached archive views.  Similarly
 190   // for releasing the descriptor.
 191   if (this->object_count_ <= 1)
 192     {
 193       this->clear_views(false);
 194       if (this->is_descriptor_opened_)
 195         {
 196           release_descriptor(this->descriptor_, false);
 197           this->is_descriptor_opened_ = false;
 198         }
 199     }
 200
 201   this->released_ = true;
 202 }
 203
 204 // Lock the file.
 205
 206 void
 207 File_read::lock(const Task* task)
 208 {
 209   gold_assert(this->released_);
 210   this->token_.add_writer(task);
 211   this->released_ = false;
 212 }
 213
 214 // Unlock the file.
 215
 216 void
 217 File_read::unlock(const Task* task)
 218 {
 219   this->release();
 220   this->token_.remove_writer(task);
 221 }
 222
 223 // Return whether the file is locked.
 224
 225 bool
 226 File_read::is_locked() const
 227 {
 228   if (!this->token_.is_writable())
 229     return true;
 230   // The file is not locked, so it should have been released.
 231   gold_assert(this->released_);
 232   return false;
 233 }
 234
 235 // See if we have a view which covers the file starting at START for
 236 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
 237 // If BYTESHIFT is not -1U, the returned View must have the specified
 238 // byte shift; otherwise, it may have any byte shift.  If VSHIFTED is
 239 // not NULL, this sets *VSHIFTED to a view which would have worked if
 240 // not for the requested BYTESHIFT.
 241
 242 inline File_read::View*
 243 File_read::find_view(off_t start, section_size_type size,
 244                      unsigned int byteshift, File_read::View** vshifted) const
 245 {
 246   if (vshifted != NULL)
 247     *vshifted = NULL;
 248
 249   off_t page = File_read::page_offset(start);
 250
 251   unsigned int bszero = 0;
 252   Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
 253                                                                     bszero));
 254
 255   while (p != this->views_.end() && p->first.first <= page)
 256     {
 257       if (p->second->start() <= start
 258           && (p->second->start() + static_cast<off_t>(p->second->size())
 259               >= start + static_cast<off_t>(size)))
 260         {
 261           if (byteshift == -1U || byteshift == p->second->byteshift())
 262             {
 263               p->second->set_accessed();
 264               return p->second;
 265             }
 266
 267           if (vshifted != NULL && *vshifted == NULL)
 268             *vshifted = p->second;
 269         }
 270
 271       ++p;
 272     }
 273
 274   return NULL;
 275 }
 276
 277 // Read SIZE bytes from the file starting at offset START.  Read into
 278 // the buffer at P.
 279
 280 void
 281 File_read::do_read(off_t start, section_size_type size, void* p)
 282 {
 283   ssize_t bytes;
 284   if (this->contents_ != NULL)
 285     {
 286       bytes = this->size_ - start;
 287       if (static_cast<section_size_type>(bytes) >= size)
 288         {
 289           memcpy(p, this->contents_ + start, size);
 290           return;
 291         }
 292     }
 293   else
 294     {
 295       this->reopen_descriptor();
 296       bytes = ::pread(this->descriptor_, p, size, start);
 297       if (static_cast<section_size_type>(bytes) == size)
 298         return;
 299
 300       if (bytes < 0)
 301         {
 302           gold_fatal(_("%s: pread failed: %s"),
 303                      this->filename().c_str(), strerror(errno));
 304           return;
 305         }
 306     }
 307
 308   gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
 309              this->filename().c_str(),
 310              static_cast<long long>(bytes),
 311              static_cast<long long>(size),
 312              static_cast<long long>(start));
 313 }
 314
 315 // Read data from the file.
 316
 317 void
 318 File_read::read(off_t start, section_size_type size, void* p)
 319 {
 320   const File_read::View* pv = this->find_view(start, size, -1U, NULL);
 321   if (pv != NULL)
 322     {
 323       memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
 324       return;
 325     }
 326
 327   this->do_read(start, size, p);
 328 }
 329
 330 // Add a new view.  There may already be an existing view at this
 331 // offset.  If there is, the new view will be larger, and should
 332 // replace the old view.
 333
 334 void
 335 File_read::add_view(File_read::View* v)
 336 {
 337   std::pair<Views::iterator, bool> ins =
 338     this->views_.insert(std::make_pair(std::make_pair(v->start(),
 339                                                       v->byteshift()),
 340                                        v));
 341   if (ins.second)
 342     return;
 343
 344   // There was an existing view at this offset.  It must not be large
 345   // enough.  We can't delete it here, since something might be using
 346   // it; we put it on a list to be deleted when the file is unlocked.
 347   File_read::View* vold = ins.first->second;
 348   gold_assert(vold->size() < v->size());
 349   if (vold->should_cache())
 350     {
 351       v->set_cache();
 352       vold->clear_cache();
 353     }
 354   this->saved_views_.push_back(vold);
 355
 356   ins.first->second = v;
 357 }
 358
 359 // Make a new view with a specified byteshift, reading the data from
 360 // the file.
 361
 362 File_read::View*
 363 File_read::make_view(off_t start, section_size_type size,
 364                      unsigned int byteshift, bool cache)
 365 {
 366   gold_assert(size > 0);
 367
 368   // Check that start and end of the view are within the file.
 369   if (start > this->size_
 370       || (static_cast<unsigned long long>(size)
 371           > static_cast<unsigned long long>(this->size_ - start)))
 372     gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
 373                  "size of file; the file may be corrupt"),
 374                    this->filename().c_str(),
 375                    static_cast<long long>(size),
 376                    static_cast<long long>(start));
 377
 378   off_t poff = File_read::page_offset(start);
 379
 380   section_size_type psize = File_read::pages(size + (start - poff));
 381
 382   if (poff + static_cast<off_t>(psize) >= this->size_)
 383     {
 384       psize = this->size_ - poff;
 385       gold_assert(psize >= size);
 386     }
 387
 388   File_read::View* v;
 389   if (this->contents_ != NULL || byteshift != 0)
 390     {
 391       unsigned char* p = new unsigned char[psize + byteshift];
 392       memset(p, 0, byteshift);
 393       this->do_read(poff, psize, p + byteshift);
 394       v = new File_read::View(poff, psize, p, byteshift, cache, false);
 395     }
 396   else
 397     {
 398       this->reopen_descriptor();
 399       void* p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE,
 400                        this->descriptor_, poff);
 401       if (p == MAP_FAILED)
 402         gold_fatal(_("%s: mmap offset %lld size %lld failed: %s"),
 403                    this->filename().c_str(),
 404                    static_cast<long long>(poff),
 405                    static_cast<long long>(psize),
 406                    strerror(errno));
 407
 408       this->mapped_bytes_ += psize;
 409
 410       const unsigned char* pbytes = static_cast<const unsigned char*>(p);
 411       v = new File_read::View(poff, psize, pbytes, 0, cache, true);
 412     }
 413
 414   this->add_view(v);
 415
 416   return v;
 417 }
 418
 419 // Find a View or make a new one, shifted as required by the file
 420 // offset OFFSET and ALIGNED.
 421
 422 File_read::View*
 423 File_read::find_or_make_view(off_t offset, off_t start,
 424                              section_size_type size, bool aligned, bool cache)
 425 {
 426   unsigned int byteshift;
 427   if (offset == 0)
 428     byteshift = 0;
 429   else
 430     {
 431       unsigned int target_size = (!parameters->target_valid()
 432                                   ? 64
 433                                   : parameters->target().get_size());
 434       byteshift = offset & ((target_size / 8) - 1);
 435
 436       // Set BYTESHIFT to the number of dummy bytes which must be
 437       // inserted before the data in order for this data to be
 438       // aligned.
 439       if (byteshift != 0)
 440         byteshift = (target_size / 8) - byteshift;
 441     }
 442
 443   // Try to find a View with the required BYTESHIFT.
 444   File_read::View* vshifted;
 445   File_read::View* v = this->find_view(offset + start, size,
 446                                        aligned ? byteshift : -1U,
 447                                        &vshifted);
 448   if (v != NULL)
 449     {
 450       if (cache)
 451         v->set_cache();
 452       return v;
 453     }
 454
 455   // If VSHIFTED is not NULL, then it has the data we need, but with
 456   // the wrong byteshift.
 457   v = vshifted;
 458   if (v != NULL)
 459     {
 460       gold_assert(aligned);
 461
 462       unsigned char* pbytes = new unsigned char[v->size() + byteshift];
 463       memset(pbytes, 0, byteshift);
 464       memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());
 465
 466       File_read::View* shifted_view = new File_read::View(v->start(), v->size(),
 467                                                           pbytes, byteshift,
 468                                                           cache, false);
 469
 470       this->add_view(shifted_view);
 471       return shifted_view;
 472     }
 473
 474   // Make a new view.  If we don't need an aligned view, use a
 475   // byteshift of 0, so that we can use mmap.
 476   return this->make_view(offset + start, size,
 477                          aligned ? byteshift : 0,
 478                          cache);
 479 }
 480
 481 // Get a view into the file.
 482
 483 const unsigned char*
 484 File_read::get_view(off_t offset, off_t start, section_size_type size,
 485                     bool aligned, bool cache)
 486 {
 487   File_read::View* pv = this->find_or_make_view(offset, start, size,
 488                                                 aligned, cache);
 489   return pv->data() + (offset + start - pv->start() + pv->byteshift());
 490 }
 491
 492 File_view*
 493 File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
 494                             bool aligned, bool cache)
 495 {
 496   File_read::View* pv = this->find_or_make_view(offset, start, size,
 497                                                 aligned, cache);
 498   pv->lock();
 499   return new File_view(*this, pv,
 500                        (pv->data()
 501                         + (offset + start - pv->start() + pv->byteshift())));
 502 }
 503
 504 // Use readv to read COUNT entries from RM starting at START.  BASE
 505 // must be added to all file offsets in RM.
 506
 507 void
 508 File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
 509                     size_t count)
 510 {
 511   unsigned char discard[File_read::page_size];
 512   iovec iov[File_read::max_readv_entries * 2];
 513   size_t iov_index = 0;
 514
 515   off_t first_offset = rm[start].file_offset;
 516   off_t last_offset = first_offset;
 517   ssize_t want = 0;
 518   for (size_t i = 0; i < count; ++i)
 519     {
 520       const Read_multiple_entry& i_entry(rm[start + i]);
 521
 522       if (i_entry.file_offset > last_offset)
 523         {
 524           size_t skip = i_entry.file_offset - last_offset;
 525           gold_assert(skip <= sizeof discard);
 526
 527           iov[iov_index].iov_base = discard;
 528           iov[iov_index].iov_len = skip;
 529           ++iov_index;
 530
 531           want += skip;
 532         }
 533
 534       iov[iov_index].iov_base = i_entry.buffer;
 535       iov[iov_index].iov_len = i_entry.size;
 536       ++iov_index;
 537
 538       want += i_entry.size;
 539
 540       last_offset = i_entry.file_offset + i_entry.size;
 541     }
 542
 543   this->reopen_descriptor();
 544
 545   gold_assert(iov_index < sizeof iov / sizeof iov[0]);
 546
 547   if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
 548     gold_fatal(_("%s: lseek failed: %s"),
 549                this->filename().c_str(), strerror(errno));
 550
 551   ssize_t got = ::readv(this->descriptor_, iov, iov_index);
 552
 553   if (got < 0)
 554     gold_fatal(_("%s: readv failed: %s"),
 555                this->filename().c_str(), strerror(errno));
 556   if (got != want)
 557     gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
 558                this->filename().c_str(),
 559                got, want, static_cast<long long>(base + first_offset));
 560 }
 561
 562 // Read several pieces of data from the file.
 563
 564 void
 565 File_read::read_multiple(off_t base, const Read_multiple& rm)
 566 {
 567   size_t count = rm.size();
 568   size_t i = 0;
 569   while (i < count)
 570     {
 571       // Find up to MAX_READV_ENTRIES consecutive entries which are
 572       // less than one page apart.
 573       const Read_multiple_entry& i_entry(rm[i]);
 574       off_t i_off = i_entry.file_offset;
 575       off_t end_off = i_off + i_entry.size;
 576       size_t j;
 577       for (j = i + 1; j < count; ++j)
 578         {
 579           if (j - i >= File_read::max_readv_entries)
 580             break;
 581           const Read_multiple_entry& j_entry(rm[j]);
 582           off_t j_off = j_entry.file_offset;
 583           gold_assert(j_off >= end_off);
 584           off_t j_end_off = j_off + j_entry.size;
 585           if (j_end_off - end_off >= File_read::page_size)
 586             break;
 587           end_off = j_end_off;
 588         }
 589
 590       if (j == i + 1)
 591         this->read(base + i_off, i_entry.size, i_entry.buffer);
 592       else
 593         {
 594           File_read::View* view = this->find_view(base + i_off,
 595                                                   end_off - i_off,
 596                                                   -1U, NULL);
 597           if (view == NULL)
 598             this->do_readv(base, rm, i, j - i);
 599           else
 600             {
 601               const unsigned char* v = (view->data()
 602                                         + (base + i_off - view->start()
 603                                            + view->byteshift()));
 604               for (size_t k = i; k < j; ++k)
 605                 {
 606                   const Read_multiple_entry& k_entry(rm[k]);
 607                   gold_assert((convert_to_section_size_type(k_entry.file_offset
 608                                                            - i_off)
 609                                + k_entry.size)
 610                               <= convert_to_section_size_type(end_off
 611                                                               - i_off));
 612                   memcpy(k_entry.buffer,
 613                          v + (k_entry.file_offset - i_off),
 614                          k_entry.size);
 615                 }
 616             }
 617         }
 618
 619       i = j;
 620     }
 621 }
 622
 623 // Mark all views as no longer cached.
 624
 625 void
 626 File_read::clear_view_cache_marks()
 627 {
 628   // Just ignore this if there are multiple objects associated with
 629   // the file.  Otherwise we will wind up uncaching and freeing some
 630   // views for other objects.
 631   if (this->object_count_ > 1)
 632     return;
 633
 634   for (Views::iterator p = this->views_.begin();
 635        p != this->views_.end();
 636        ++p)
 637     p->second->clear_cache();
 638   for (Saved_views::iterator p = this->saved_views_.begin();
 639        p != this->saved_views_.end();
 640        ++p)
 641     (*p)->clear_cache();
 642 }
 643
 644 // Remove all the file views.  For a file which has multiple
 645 // associated objects (i.e., an archive), we keep accessed views
 646 // around until next time, in the hopes that they will be useful for
 647 // the next object.
 648
 649 void
 650 File_read::clear_views(bool destroying)
 651 {
 652   Views::iterator p = this->views_.begin();
 653   while (p != this->views_.end())
 654     {
 655       bool should_delete;
 656       if (p->second->is_locked())
 657         should_delete = false;
 658       else if (destroying)
 659         should_delete = true;
 660       else if (p->second->should_cache())
 661         should_delete = false;
 662       else if (this->object_count_ > 1 && p->second->accessed())
 663         should_delete = false;
 664       else
 665         should_delete = true;
 666
 667       if (should_delete)
 668         {
 669           delete p->second;
 670
 671           // map::erase invalidates only the iterator to the deleted
 672           // element.
 673           Views::iterator pe = p;
 674           ++p;
 675           this->views_.erase(pe);
 676         }
 677       else
 678         {
 679           gold_assert(!destroying);
 680           p->second->clear_accessed();
 681           ++p;
 682         }
 683     }
 684
 685   Saved_views::iterator q = this->saved_views_.begin();
 686   while (q != this->saved_views_.end())
 687     {
 688       if (!(*q)->is_locked())
 689         {
 690           delete *q;
 691           q = this->saved_views_.erase(q);
 692         }
 693       else
 694         {
 695           gold_assert(!destroying);
 696           ++q;
 697         }
 698     }
 699 }
 700
 701 // Print statistical information to stderr.  This is used for --stats.
 702
 703 void
 704 File_read::print_stats()
 705 {
 706   fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
 707           program_name, File_read::total_mapped_bytes);
 708   fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
 709           program_name, File_read::maximum_mapped_bytes);
 710 }
 711
 712 // Class File_view.
 713
 714 File_view::~File_view()
 715 {
 716   gold_assert(this->file_.is_locked());
 717   this->view_->unlock();
 718 }
 719
 720 // Class Input_file.
 721
 722 // Create a file for testing.
 723
 724 Input_file::Input_file(const Task* task, const char* name,
 725                        const unsigned char* contents, off_t size)
 726   : file_()
 727 {
 728   this->input_argument_ =
 729     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
 730                             "", false, Position_dependent_options());
 731   bool ok = this->file_.open(task, name, contents, size);
 732   gold_assert(ok);
 733 }
 734
 735 // Return the position dependent options in force for this file.
 736
 737 const Position_dependent_options&
 738 Input_file::options() const
 739 {
 740   return this->input_argument_->options();
 741 }
 742
 743 // Return the name given by the user.  For -lc this will return "c".
 744
 745 const char*
 746 Input_file::name() const
 747 {
 748   return this->input_argument_->name();
 749 }
 750
 751 // Return whether this file is in a system directory.
 752
 753 bool
 754 Input_file::is_in_system_directory() const
 755 {
 756   if (this->is_in_sysroot())
 757     return true;
 758   return parameters->options().is_in_system_directory(this->filename());
 759 }
 760
 761 // Return whether we are only reading symbols.
 762
 763 bool
 764 Input_file::just_symbols() const
 765 {
 766   return this->input_argument_->just_symbols();
 767 }
 768
 769 // Return whether this is a file that we will search for in the list
 770 // of directories.
 771
 772 bool
 773 Input_file::will_search_for() const
 774 {
 775   return (!IS_ABSOLUTE_PATH(this->input_argument_->name())
 776           && (this->input_argument_->is_lib()
 777               || this->input_argument_->is_searched_file()
 778               || this->input_argument_->extra_search_path() != NULL));
 779 }
 780
 781 // Return the file last modification time.  Calls gold_fatal if the stat
 782 // system call failed.
 783
 784 Timespec
 785 File_read::get_mtime()
 786 {
 787   struct stat file_stat;
 788   this->reopen_descriptor();
 789
 790   if (fstat(this->descriptor_, &file_stat) < 0)
 791     gold_fatal(_("%s: stat failed: %s"), this->name_.c_str(),
 792                strerror(errno));
 793   // TODO: do a configure check if st_mtim is present and get the
 794   // nanoseconds part if it is.
 795   return Timespec(file_stat.st_mtime, 0);
 796 }
 797
 798 // Open the file.
 799
 800 // If the filename is not absolute, we assume it is in the current
 801 // directory *except* when:
 802 //    A) input_argument_->is_lib() is true;
 803 //    B) input_argument_->is_searched_file() is true; or
 804 //    C) input_argument_->extra_search_path() is not empty.
 805 // In each, we look in extra_search_path + library_path to find
 806 // the file location, rather than the current directory.
 807
 808 bool
 809 Input_file::open(const Dirsearch& dirpath, const Task* task, int *pindex)
 810 {
 811   std::string name;
 812
 813   // Case 1: name is an absolute file, just try to open it
 814   // Case 2: name is relative but is_lib is false, is_searched_file is false,
 815   //         and extra_search_path is empty
 816   if (IS_ABSOLUTE_PATH(this->input_argument_->name())
 817       || (!this->input_argument_->is_lib()
 818           && !this->input_argument_->is_searched_file()
 819           && this->input_argument_->extra_search_path() == NULL))
 820     {
 821       name = this->input_argument_->name();
 822       this->found_name_ = name;
 823     }
 824   // Case 3: is_lib is true or is_searched_file is true
 825   else if (this->input_argument_->is_lib()
 826            || this->input_argument_->is_searched_file())
 827     {
 828       // We don't yet support extra_search_path with -l.
 829       gold_assert(this->input_argument_->extra_search_path() == NULL);
 830       std::string n1, n2;
 831       if (this->input_argument_->is_lib())
 832         {
 833           n1 = "lib";
 834           n1 += this->input_argument_->name();
 835           if (parameters->options().is_static()
 836               || !this->input_argument_->options().Bdynamic())
 837             n1 += ".a";
 838           else
 839             {
 840               n2 = n1 + ".a";
 841               n1 += ".so";
 842             }
 843         }
 844       else
 845         n1 = this->input_argument_->name();
 846       name = dirpath.find(n1, n2, &this->is_in_sysroot_, pindex);
 847       if (name.empty())
 848         {
 849           gold_error(_("cannot find %s%s"),
 850                      this->input_argument_->is_lib() ? "-l" : "",
 851                      this->input_argument_->name());
 852           return false;
 853         }
 854       if (n2.empty() || name[name.length() - 1] == 'o')
 855         this->found_name_ = n1;
 856       else
 857         this->found_name_ = n2;
 858     }
 859   // Case 4: extra_search_path is not empty
 860   else
 861     {
 862       gold_assert(this->input_argument_->extra_search_path() != NULL);
 863
 864       // First, check extra_search_path.
 865       name = this->input_argument_->extra_search_path();
 866       if (!IS_DIR_SEPARATOR (name[name.length() - 1]))
 867         name += '/';
 868       name += this->input_argument_->name();
 869       struct stat dummy_stat;
 870       if (*pindex > 0 || ::stat(name.c_str(), &dummy_stat) < 0)
 871         {
 872           // extra_search_path failed, so check the normal search-path.
 873           int index = *pindex;
 874           if (index > 0)
 875             --index;
 876           name = dirpath.find(this->input_argument_->name(), "",
 877                               &this->is_in_sysroot_, &index);
 878           if (name.empty())
 879             {
 880               gold_error(_("cannot find %s"),
 881                          this->input_argument_->name());
 882               return false;
 883             }
 884           *pindex = index + 1;
 885         }
 886       this->found_name_ = this->input_argument_->name();
 887     }
 888
 889   // Now that we've figured out where the file lives, try to open it.
 890
 891   General_options::Object_format format =
 892     this->input_argument_->options().format_enum();
 893   bool ok;
 894   if (format == General_options::OBJECT_FORMAT_ELF)
 895     ok = this->file_.open(task, name);
 896   else
 897     {
 898       gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
 899       ok = this->open_binary(task, name);
 900     }
 901
 902   if (!ok)
 903     {
 904       gold_error(_("cannot open %s: %s"),
 905                  name.c_str(), strerror(errno));
 906       return false;
 907     }
 908
 909   return true;
 910 }
 911
 912 // Open a file for --format binary.
 913
 914 bool
 915 Input_file::open_binary(const Task* task, const std::string& name)
 916 {
 917   // In order to open a binary file, we need machine code, size, and
 918   // endianness.  We may not have a valid target at this point, in
 919   // which case we use the default target.
 920   parameters_force_valid_target();
 921   const Target& target(parameters->target());
 922
 923   Binary_to_elf binary_to_elf(target.machine_code(),
 924                               target.get_size(),
 925                               target.is_big_endian(),
 926                               name);
 927   if (!binary_to_elf.convert(task))
 928     return false;
 929   return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
 930                           binary_to_elf.converted_size());
 931 }
 932
 933 } // End namespace gold.