1 // fileread.cc -- read files for gold
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
31 #include "filenames.h"
34 #include "parameters.h"
36 #include "dirsearch.h"
39 #include "descriptors.h"
45 // Class File_read::View.
47 File_read::View::~View()
49 gold_assert(!this->is_locked());
54 if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
55 gold_warning(_("munmap failed: %s"), strerror(errno));
57 File_read::current_mapped_bytes -= this->size_;
62 File_read::View::lock()
68 File_read::View::unlock()
70 gold_assert(this->lock_count_ > 0);
75 File_read::View::is_locked()
77 return this->lock_count_ > 0;
82 // The File_read static variables.
83 unsigned long long File_read::total_mapped_bytes;
84 unsigned long long File_read::current_mapped_bytes;
85 unsigned long long File_read::maximum_mapped_bytes;
87 File_read::~File_read()
89 gold_assert(this->token_.is_writable());
90 if (this->is_descriptor_opened_)
92 release_descriptor(this->descriptor_, true);
93 this->descriptor_ = -1;
94 this->is_descriptor_opened_ = false;
97 this->clear_views(true);
103 File_read::open(const Task* task, const std::string& name)
105 gold_assert(this->token_.is_writable()
106 && this->descriptor_ < 0
107 && !this->is_descriptor_opened_
108 && this->name_.empty());
111 this->descriptor_ = open_descriptor(-1, this->name_.c_str(),
114 if (this->descriptor_ >= 0)
116 this->is_descriptor_opened_ = true;
118 if (::fstat(this->descriptor_, &s) < 0)
119 gold_error(_("%s: fstat failed: %s"),
120 this->name_.c_str(), strerror(errno));
121 this->size_ = s.st_size;
122 gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
123 this->name_.c_str());
125 this->token_.add_writer(task);
128 return this->descriptor_ >= 0;
131 // Open the file with the contents in memory.
134 File_read::open(const Task* task, const std::string& name,
135 const unsigned char* contents, off_t size)
137 gold_assert(this->token_.is_writable()
138 && this->descriptor_ < 0
139 && !this->is_descriptor_opened_
140 && this->name_.empty());
142 this->contents_ = contents;
144 this->token_.add_writer(task);
148 // Reopen a descriptor if necessary.
151 File_read::reopen_descriptor()
153 if (!this->is_descriptor_opened_)
155 this->descriptor_ = open_descriptor(this->descriptor_,
158 if (this->descriptor_ < 0)
159 gold_fatal(_("could not reopen file %s"), this->name_.c_str());
160 this->is_descriptor_opened_ = true;
164 // Release the file. This is called when we are done with the file in
170 gold_assert(this->is_locked());
172 File_read::total_mapped_bytes += this->mapped_bytes_;
173 File_read::current_mapped_bytes += this->mapped_bytes_;
174 this->mapped_bytes_ = 0;
175 if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
176 File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
178 // Only clear views if there is only one attached object. Otherwise
179 // we waste time trying to clear cached archive views. Similarly
180 // for releasing the descriptor.
181 if (this->object_count_ <= 1)
183 this->clear_views(false);
184 if (this->is_descriptor_opened_)
186 release_descriptor(this->descriptor_, false);
187 this->is_descriptor_opened_ = false;
191 this->released_ = true;
197 File_read::lock(const Task* task)
199 gold_assert(this->released_);
200 this->token_.add_writer(task);
201 this->released_ = false;
207 File_read::unlock(const Task* task)
210 this->token_.remove_writer(task);
213 // Return whether the file is locked.
216 File_read::is_locked() const
218 if (!this->token_.is_writable())
220 // The file is not locked, so it should have been released.
221 gold_assert(this->released_);
225 // See if we have a view which covers the file starting at START for
226 // SIZE bytes. Return a pointer to the View if found, NULL if not.
227 // If BYTESHIFT is not -1U, the returned View must have the specified
228 // byte shift; otherwise, it may have any byte shift. If VSHIFTED is
229 // not NULL, this sets *VSHIFTED to a view which would have worked if
230 // not for the requested BYTESHIFT.
232 inline File_read::View*
233 File_read::find_view(off_t start, section_size_type size,
234 unsigned int byteshift, File_read::View** vshifted) const
236 if (vshifted != NULL)
239 off_t page = File_read::page_offset(start);
241 unsigned int bszero = 0;
242 Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
245 while (p != this->views_.end() && p->first.first <= page)
247 if (p->second->start() <= start
248 && (p->second->start() + static_cast<off_t>(p->second->size())
249 >= start + static_cast<off_t>(size)))
251 if (byteshift == -1U || byteshift == p->second->byteshift())
253 p->second->set_accessed();
257 if (vshifted != NULL && *vshifted == NULL)
258 *vshifted = p->second;
267 // Read SIZE bytes from the file starting at offset START. Read into
271 File_read::do_read(off_t start, section_size_type size, void* p)
274 if (this->contents_ != NULL)
276 bytes = this->size_ - start;
277 if (static_cast<section_size_type>(bytes) >= size)
279 memcpy(p, this->contents_ + start, size);
285 this->reopen_descriptor();
286 bytes = ::pread(this->descriptor_, p, size, start);
287 if (static_cast<section_size_type>(bytes) == size)
292 gold_fatal(_("%s: pread failed: %s"),
293 this->filename().c_str(), strerror(errno));
298 gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
299 this->filename().c_str(),
300 static_cast<long long>(bytes),
301 static_cast<long long>(size),
302 static_cast<long long>(start));
305 // Read data from the file.
308 File_read::read(off_t start, section_size_type size, void* p)
310 const File_read::View* pv = this->find_view(start, size, -1U, NULL);
313 memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
317 this->do_read(start, size, p);
320 // Add a new view. There may already be an existing view at this
321 // offset. If there is, the new view will be larger, and should
322 // replace the old view.
325 File_read::add_view(File_read::View* v)
327 std::pair<Views::iterator, bool> ins =
328 this->views_.insert(std::make_pair(std::make_pair(v->start(),
334 // There was an existing view at this offset. It must not be large
335 // enough. We can't delete it here, since something might be using
336 // it; we put it on a list to be deleted when the file is unlocked.
337 File_read::View* vold = ins.first->second;
338 gold_assert(vold->size() < v->size());
339 if (vold->should_cache())
344 this->saved_views_.push_back(vold);
346 ins.first->second = v;
349 // Make a new view with a specified byteshift, reading the data from
353 File_read::make_view(off_t start, section_size_type size,
354 unsigned int byteshift, bool cache)
356 gold_assert(size > 0);
358 // Check that start and end of the view are within the file.
359 if (start > this->size_
360 || (static_cast<unsigned long long>(size)
361 > static_cast<unsigned long long>(this->size_ - start)))
362 gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
363 "size of file; the file may be corrupt"),
364 this->filename().c_str(),
365 static_cast<long long>(size),
366 static_cast<long long>(start));
368 off_t poff = File_read::page_offset(start);
370 section_size_type psize = File_read::pages(size + (start - poff));
372 if (poff + static_cast<off_t>(psize) >= this->size_)
374 psize = this->size_ - poff;
375 gold_assert(psize >= size);
379 if (this->contents_ != NULL || byteshift != 0)
381 unsigned char* p = new unsigned char[psize + byteshift];
382 memset(p, 0, byteshift);
383 this->do_read(poff, psize, p + byteshift);
384 v = new File_read::View(poff, psize, p, byteshift, cache, false);
388 this->reopen_descriptor();
389 void* p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE,
390 this->descriptor_, poff);
392 gold_fatal(_("%s: mmap offset %lld size %lld failed: %s"),
393 this->filename().c_str(),
394 static_cast<long long>(poff),
395 static_cast<long long>(psize),
398 this->mapped_bytes_ += psize;
400 const unsigned char* pbytes = static_cast<const unsigned char*>(p);
401 v = new File_read::View(poff, psize, pbytes, 0, cache, true);
409 // Find a View or make a new one, shifted as required by the file
410 // offset OFFSET and ALIGNED.
413 File_read::find_or_make_view(off_t offset, off_t start,
414 section_size_type size, bool aligned, bool cache)
416 unsigned int byteshift;
421 unsigned int target_size = (!parameters->target_valid()
423 : parameters->target().get_size());
424 byteshift = offset & ((target_size / 8) - 1);
426 // Set BYTESHIFT to the number of dummy bytes which must be
427 // inserted before the data in order for this data to be
430 byteshift = (target_size / 8) - byteshift;
433 // Try to find a View with the required BYTESHIFT.
434 File_read::View* vshifted;
435 File_read::View* v = this->find_view(offset + start, size,
436 aligned ? byteshift : -1U,
445 // If VSHIFTED is not NULL, then it has the data we need, but with
446 // the wrong byteshift.
450 gold_assert(aligned);
452 unsigned char* pbytes = new unsigned char[v->size() + byteshift];
453 memset(pbytes, 0, byteshift);
454 memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());
456 File_read::View* shifted_view = new File_read::View(v->start(), v->size(),
460 this->add_view(shifted_view);
464 // Make a new view. If we don't need an aligned view, use a
465 // byteshift of 0, so that we can use mmap.
466 return this->make_view(offset + start, size,
467 aligned ? byteshift : 0,
471 // Get a view into the file.
474 File_read::get_view(off_t offset, off_t start, section_size_type size,
475 bool aligned, bool cache)
477 File_read::View* pv = this->find_or_make_view(offset, start, size,
479 return pv->data() + (offset + start - pv->start() + pv->byteshift());
483 File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
484 bool aligned, bool cache)
486 File_read::View* pv = this->find_or_make_view(offset, start, size,
489 return new File_view(*this, pv,
491 + (offset + start - pv->start() + pv->byteshift())));
494 // Use readv to read COUNT entries from RM starting at START. BASE
495 // must be added to all file offsets in RM.
498 File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
501 unsigned char discard[File_read::page_size];
502 iovec iov[File_read::max_readv_entries * 2];
503 size_t iov_index = 0;
505 off_t first_offset = rm[start].file_offset;
506 off_t last_offset = first_offset;
508 for (size_t i = 0; i < count; ++i)
510 const Read_multiple_entry& i_entry(rm[start + i]);
512 if (i_entry.file_offset > last_offset)
514 size_t skip = i_entry.file_offset - last_offset;
515 gold_assert(skip <= sizeof discard);
517 iov[iov_index].iov_base = discard;
518 iov[iov_index].iov_len = skip;
524 iov[iov_index].iov_base = i_entry.buffer;
525 iov[iov_index].iov_len = i_entry.size;
528 want += i_entry.size;
530 last_offset = i_entry.file_offset + i_entry.size;
533 this->reopen_descriptor();
535 gold_assert(iov_index < sizeof iov / sizeof iov[0]);
537 if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
538 gold_fatal(_("%s: lseek failed: %s"),
539 this->filename().c_str(), strerror(errno));
541 ssize_t got = ::readv(this->descriptor_, iov, iov_index);
544 gold_fatal(_("%s: readv failed: %s"),
545 this->filename().c_str(), strerror(errno));
547 gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
548 this->filename().c_str(),
549 got, want, static_cast<long long>(base + first_offset));
552 // Read several pieces of data from the file.
555 File_read::read_multiple(off_t base, const Read_multiple& rm)
557 size_t count = rm.size();
561 // Find up to MAX_READV_ENTRIES consecutive entries which are
562 // less than one page apart.
563 const Read_multiple_entry& i_entry(rm[i]);
564 off_t i_off = i_entry.file_offset;
565 off_t end_off = i_off + i_entry.size;
567 for (j = i + 1; j < count; ++j)
569 if (j - i >= File_read::max_readv_entries)
571 const Read_multiple_entry& j_entry(rm[j]);
572 off_t j_off = j_entry.file_offset;
573 gold_assert(j_off >= end_off);
574 off_t j_end_off = j_off + j_entry.size;
575 if (j_end_off - end_off >= File_read::page_size)
581 this->read(base + i_off, i_entry.size, i_entry.buffer);
584 File_read::View* view = this->find_view(base + i_off,
588 this->do_readv(base, rm, i, j - i);
591 const unsigned char* v = (view->data()
592 + (base + i_off - view->start()
593 + view->byteshift()));
594 for (size_t k = i; k < j; ++k)
596 const Read_multiple_entry& k_entry(rm[k]);
597 gold_assert((convert_to_section_size_type(k_entry.file_offset
600 <= convert_to_section_size_type(end_off
602 memcpy(k_entry.buffer,
603 v + (k_entry.file_offset - i_off),
613 // Mark all views as no longer cached.
616 File_read::clear_view_cache_marks()
618 // Just ignore this if there are multiple objects associated with
619 // the file. Otherwise we will wind up uncaching and freeing some
620 // views for other objects.
621 if (this->object_count_ > 1)
624 for (Views::iterator p = this->views_.begin();
625 p != this->views_.end();
627 p->second->clear_cache();
628 for (Saved_views::iterator p = this->saved_views_.begin();
629 p != this->saved_views_.end();
634 // Remove all the file views. For a file which has multiple
635 // associated objects (i.e., an archive), we keep accessed views
636 // around until next time, in the hopes that they will be useful for
640 File_read::clear_views(bool destroying)
642 Views::iterator p = this->views_.begin();
643 while (p != this->views_.end())
646 if (p->second->is_locked())
647 should_delete = false;
649 should_delete = true;
650 else if (p->second->should_cache())
651 should_delete = false;
652 else if (this->object_count_ > 1 && p->second->accessed())
653 should_delete = false;
655 should_delete = true;
661 // map::erase invalidates only the iterator to the deleted
663 Views::iterator pe = p;
665 this->views_.erase(pe);
669 gold_assert(!destroying);
670 p->second->clear_accessed();
675 Saved_views::iterator q = this->saved_views_.begin();
676 while (q != this->saved_views_.end())
678 if (!(*q)->is_locked())
681 q = this->saved_views_.erase(q);
685 gold_assert(!destroying);
691 // Print statistical information to stderr. This is used for --stats.
694 File_read::print_stats()
696 fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
697 program_name, File_read::total_mapped_bytes);
698 fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
699 program_name, File_read::maximum_mapped_bytes);
704 File_view::~File_view()
706 gold_assert(this->file_.is_locked());
707 this->view_->unlock();
712 // Create a file for testing.
714 Input_file::Input_file(const Task* task, const char* name,
715 const unsigned char* contents, off_t size)
718 this->input_argument_ =
719 new Input_file_argument(name, false, "", false,
720 Position_dependent_options());
721 bool ok = file_.open(task, name, contents, size);
725 // Return the position dependent options in force for this file.
727 const Position_dependent_options&
728 Input_file::options() const
730 return this->input_argument_->options();
733 // Return the name given by the user. For -lc this will return "c".
736 Input_file::name() const
738 return this->input_argument_->name();
741 // Return whether we are only reading symbols.
744 Input_file::just_symbols() const
746 return this->input_argument_->just_symbols();
751 // If the filename is not absolute, we assume it is in the current
752 // directory *except* when:
753 // A) input_argument_->is_lib() is true; or
754 // B) input_argument_->extra_search_path() is not empty.
755 // In both cases, we look in extra_search_path + library_path to find
756 // the file location, rather than the current directory.
759 Input_file::open(const General_options& options, const Dirsearch& dirpath,
764 // Case 1: name is an absolute file, just try to open it
765 // Case 2: name is relative but is_lib is false and extra_search_path
767 if (IS_ABSOLUTE_PATH (this->input_argument_->name())
768 || (!this->input_argument_->is_lib()
769 && this->input_argument_->extra_search_path() == NULL))
771 name = this->input_argument_->name();
772 this->found_name_ = name;
774 // Case 3: is_lib is true
775 else if (this->input_argument_->is_lib())
777 // We don't yet support extra_search_path with -l.
778 gold_assert(this->input_argument_->extra_search_path() == NULL);
779 std::string n1("lib");
780 n1 += this->input_argument_->name();
782 if (options.is_static()
783 || !this->input_argument_->options().Bdynamic())
790 name = dirpath.find(n1, n2, &this->is_in_sysroot_);
793 gold_error(_("cannot find -l%s"),
794 this->input_argument_->name());
797 if (n2.empty() || name[name.length() - 1] == 'o')
798 this->found_name_ = n1;
800 this->found_name_ = n2;
802 // Case 4: extra_search_path is not empty
805 gold_assert(this->input_argument_->extra_search_path() != NULL);
807 // First, check extra_search_path.
808 name = this->input_argument_->extra_search_path();
809 if (!IS_DIR_SEPARATOR (name[name.length() - 1]))
811 name += this->input_argument_->name();
812 struct stat dummy_stat;
813 if (::stat(name.c_str(), &dummy_stat) < 0)
815 // extra_search_path failed, so check the normal search-path.
816 name = dirpath.find(this->input_argument_->name(), "",
817 &this->is_in_sysroot_);
820 gold_error(_("cannot find %s"),
821 this->input_argument_->name());
825 this->found_name_ = this->input_argument_->name();
828 // Now that we've figured out where the file lives, try to open it.
830 General_options::Object_format format =
831 this->input_argument_->options().format_enum();
833 if (format == General_options::OBJECT_FORMAT_ELF)
834 ok = this->file_.open(task, name);
837 gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
838 ok = this->open_binary(options, task, name);
843 gold_error(_("cannot open %s: %s"),
844 name.c_str(), strerror(errno));
851 // Open a file for --format binary.
854 Input_file::open_binary(const General_options&,
855 const Task* task, const std::string& name)
857 // In order to open a binary file, we need machine code, size, and
858 // endianness. We may not have a valid target at this point, in
859 // which case we use the default target.
860 const Target* target;
861 if (parameters->target_valid())
862 target = ¶meters->target();
864 target = ¶meters->default_target();
866 Binary_to_elf binary_to_elf(target->machine_code(),
868 target->is_big_endian(),
870 if (!binary_to_elf.convert(task))
872 return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
873 binary_to_elf.converted_size());
876 } // End namespace gold.