binutils-gdb/gold/fileread.cc
2007-09-22 21:02:10 +00:00

400 lines
8.8 KiB
C++

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