417 lines
9.2 KiB
C++
417 lines
9.2 KiB
C++
// fileread.cc -- read files for gold
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// Copyright 2006, 2007 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#include <cstring>
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#include <cerrno>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include "options.h"
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#include "dirsearch.h"
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#include "fileread.h"
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namespace gold
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{
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// Class File_read::View.
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File_read::View::~View()
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{
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gold_assert(!this->is_locked());
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if (!this->mapped_)
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delete[] this->data_;
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else
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{
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if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
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fprintf(stderr, _("%s: munmap failed: %s\n"),
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program_name, strerror(errno));
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}
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}
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void
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File_read::View::lock()
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{
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++this->lock_count_;
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}
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void
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File_read::View::unlock()
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{
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gold_assert(this->lock_count_ > 0);
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--this->lock_count_;
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}
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bool
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File_read::View::is_locked()
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{
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return this->lock_count_ > 0;
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}
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// Class File_read.
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// The File_read class is designed to support file descriptor caching,
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// but this is not currently implemented.
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File_read::~File_read()
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{
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gold_assert(this->lock_count_ == 0);
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if (this->descriptor_ >= 0)
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{
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if (close(this->descriptor_) < 0)
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fprintf(stderr, _("%s: warning: close(%s) failed: %s"),
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program_name, this->name_.c_str(), strerror(errno));
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this->descriptor_ = -1;
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}
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this->name_.clear();
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this->clear_views(true);
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}
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// Open the file.
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bool
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File_read::open(const std::string& name)
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{
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gold_assert(this->lock_count_ == 0
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&& this->descriptor_ < 0
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&& this->name_.empty());
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this->name_ = name;
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this->descriptor_ = ::open(this->name_.c_str(), O_RDONLY);
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if (this->descriptor_ >= 0)
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{
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struct stat s;
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if (::fstat(this->descriptor_, &s) < 0)
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{
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fprintf(stderr, _("%s: %s: fstat failed: %s"), program_name,
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this->name_.c_str(), strerror(errno));
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gold_exit(false);
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}
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this->size_ = s.st_size;
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}
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++this->lock_count_;
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return this->descriptor_ >= 0;
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}
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// Open the file for testing purposes.
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bool
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File_read::open(const std::string& name, const unsigned char* contents,
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off_t size)
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{
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gold_assert(this->lock_count_ == 0
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&& this->descriptor_ < 0
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&& this->name_.empty());
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this->name_ = name;
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this->contents_ = contents;
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this->size_ = size;
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++this->lock_count_;
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return true;
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}
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void
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File_read::lock()
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{
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++this->lock_count_;
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}
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void
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File_read::unlock()
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{
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gold_assert(this->lock_count_ > 0);
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--this->lock_count_;
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if (this->lock_count_ == 0)
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this->clear_views(false);
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}
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bool
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File_read::is_locked()
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{
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return this->lock_count_ > 0;
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}
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// See if we have a view which covers the file starting at START for
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// SIZE bytes. Return a pointer to the View if found, NULL if not.
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inline File_read::View*
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File_read::find_view(off_t start, off_t size)
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{
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off_t page = File_read::page_offset(start);
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Views::iterator p = this->views_.find(page);
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if (p == this->views_.end())
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return NULL;
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if (p->second->size() - (start - page) < size)
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return NULL;
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return p->second;
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}
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// Read SIZE bytes from the file starting at offset START. Read into
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// the buffer at P.
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void
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File_read::do_read(off_t start, off_t size, void* p)
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{
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gold_assert(this->lock_count_ > 0);
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off_t bytes;
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if (this->contents_ != NULL)
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{
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bytes = this->size_ - start;
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if (bytes >= size)
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{
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memcpy(p, this->contents_ + start, size);
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return;
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}
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}
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else
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{
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bytes = ::pread(this->descriptor_, p, size, start);
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if (bytes == size)
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return;
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if (bytes < 0)
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{
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fprintf(stderr, _("%s: %s: pread failed: %s\n"),
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program_name, this->filename().c_str(), strerror(errno));
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gold_exit(false);
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}
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}
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fprintf(stderr,
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_("%s: %s: file too short: read only %lld of %lld bytes at %lld\n"),
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program_name, this->filename().c_str(),
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static_cast<long long>(bytes),
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static_cast<long long>(size),
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static_cast<long long>(start));
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gold_exit(false);
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}
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// Read data from the file.
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void
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File_read::read(off_t start, off_t size, void* p)
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{
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gold_assert(this->lock_count_ > 0);
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File_read::View* pv = this->find_view(start, size);
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if (pv != NULL)
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{
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memcpy(p, pv->data() + (start - pv->start()), size);
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return;
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}
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this->do_read(start, size, p);
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}
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// Find an existing view or make a new one.
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File_read::View*
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File_read::find_or_make_view(off_t start, off_t size, bool cache)
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{
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gold_assert(this->lock_count_ > 0);
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off_t poff = File_read::page_offset(start);
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File_read::View* const vnull = NULL;
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std::pair<Views::iterator, bool> ins =
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this->views_.insert(std::make_pair(poff, vnull));
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if (!ins.second)
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{
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// There was an existing view at this offset.
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File_read::View* v = ins.first->second;
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if (v->size() - (start - v->start()) >= size)
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{
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if (cache)
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v->set_cache();
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return v;
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}
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// This view is not large enough.
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this->saved_views_.push_back(v);
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}
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// We need to read data from the file. We read full pages for
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// greater efficiency on small files.
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off_t psize = File_read::pages(size + (start - poff));
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if (poff + psize >= this->size_)
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{
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psize = this->size_ - poff;
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gold_assert(psize >= size);
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}
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File_read::View* v;
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if (this->contents_ != NULL)
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{
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unsigned char* p = new unsigned char[psize];
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this->do_read(poff, psize, p);
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v = new File_read::View(poff, psize, p, cache, false);
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}
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else
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{
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void* p = ::mmap(NULL, psize, PROT_READ, MAP_SHARED,
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this->descriptor_, poff);
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if (p == MAP_FAILED)
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{
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fprintf(stderr, _("%s: %s: mmap offset %lld size %lld failed: %s\n"),
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program_name, this->filename().c_str(),
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static_cast<long long>(poff),
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static_cast<long long>(psize),
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strerror(errno));
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gold_exit(false);
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}
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const unsigned char* pbytes = static_cast<const unsigned char*>(p);
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v = new File_read::View(poff, psize, pbytes, cache, true);
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}
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ins.first->second = v;
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return v;
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}
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// This implementation of get_view just reads into a memory buffer,
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// which we store on view_list_. At some point we should support
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// mmap.
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const unsigned char*
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File_read::get_view(off_t start, off_t size, bool cache)
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{
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gold_assert(this->lock_count_ > 0);
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File_read::View* pv = this->find_or_make_view(start, size, cache);
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return pv->data() + (start - pv->start());
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}
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File_view*
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File_read::get_lasting_view(off_t start, off_t size, bool cache)
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{
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gold_assert(this->lock_count_ > 0);
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File_read::View* pv = this->find_or_make_view(start, size, cache);
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pv->lock();
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return new File_view(*this, pv, pv->data() + (start - pv->start()));
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}
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// Remove all the file views.
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void
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File_read::clear_views(bool destroying)
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{
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for (Views::iterator p = this->views_.begin();
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p != this->views_.end();
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++p)
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{
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if (!p->second->is_locked()
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&& (destroying || !p->second->should_cache()))
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delete p->second;
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else
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{
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gold_assert(!destroying);
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this->saved_views_.push_back(p->second);
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}
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}
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this->views_.clear();
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Saved_views::iterator p = this->saved_views_.begin();
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while (p != this->saved_views_.end())
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{
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if (!(*p)->is_locked()
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&& (destroying || !(*p)->should_cache()))
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{
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delete *p;
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p = this->saved_views_.erase(p);
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}
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else
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{
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gold_assert(!destroying);
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++p;
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}
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}
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}
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// Class File_view.
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File_view::~File_view()
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{
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gold_assert(this->file_.is_locked());
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this->view_->unlock();
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}
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// Class Input_file.
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// Create a file for testing.
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Input_file::Input_file(const char* name, const unsigned char* contents,
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off_t size)
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: file_()
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{
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this->input_argument_ =
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new Input_file_argument(name, false, Position_dependent_options());
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bool ok = file_.open(name, contents, size);
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gold_assert(ok);
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}
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// Open the file.
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void
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Input_file::open(const General_options& options, const Dirsearch& dirpath)
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{
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std::string name;
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if (!this->input_argument_->is_lib())
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name = this->input_argument_->name();
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else
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{
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std::string n1("lib");
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n1 += this->input_argument_->name();
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std::string n2;
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if (options.is_static())
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n1 += ".a";
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else
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{
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n2 = n1 + ".a";
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n1 += ".so";
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}
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name = dirpath.find(n1, n2);
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if (name.empty())
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{
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fprintf(stderr, _("%s: cannot find %s\n"), program_name,
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this->input_argument_->name());
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gold_exit(false);
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}
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}
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if (!this->file_.open(name))
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{
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fprintf(stderr, _("%s: cannot open %s: %s\n"), program_name,
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name.c_str(), strerror(errno));
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gold_exit(false);
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}
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}
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} // End namespace gold.
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