encfs/base/ConfigReader.cpp

/*****************************************************************************
 * Author:   Valient Gough <vgough@pobox.com>
 *
 *****************************************************************************
 * Copyright (c) 2004-2013, Valient Gough
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "base/ConfigReader.h"

#include <glog/logging.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <cstring>


using namespace std;


ConfigReader::ConfigReader()
{
}

ConfigReader::~ConfigReader()
{
}

// read the entire file into a ConfigVar instance and then use that to decode
// into mapped variables.
bool ConfigReader::load(const char *fileName)
{
  struct stat stbuf;
  memset( &stbuf, 0, sizeof(struct stat));
  if( lstat( fileName, &stbuf ) != 0)
    return false;

  int size = stbuf.st_size;

  int fd = open( fileName, O_RDONLY );
  if(fd < 0)
    return false;

  char *buf = new char[size];

  int res = ::read( fd, buf, size );
  close( fd );

  if( res != size )
  {
    LOG(WARNING) << "Partial read of config file, expecting " 
      << size << " bytes, got " << res;
    delete[] buf;
    return false;
  }

  ConfigVar in;
  in.write( (unsigned char *)buf, size );
  delete[] buf;

  return loadFromVar( in );
}

bool ConfigReader::loadFromVar(ConfigVar &in)
{
  in.resetOffset();

  // parse.
  int numEntries = in.readInt();

  for(int i=0; i<numEntries; ++i)
  {
    string key, value;
    in >> key >> value;

    if(key.length() == 0)
    {
      LOG(ERROR) << "Invalid key encoding in buffer";
      return false;
    }
    ConfigVar newVar( value );
    vars.insert( make_pair( key, newVar ) );
  }

  return true;
}

bool ConfigReader::save(const char *fileName) const
{
  // write everything to a ConfigVar, then output to disk
  ConfigVar out = toVar();

  int fd = ::open( fileName, O_RDWR | O_CREAT, 0640 );
  if(fd >= 0)
  {
    int retVal = ::write( fd, out.buffer(), out.size() );
    close( fd );
    if(retVal != out.size())
    {
      LOG(ERROR) << "Error writing to config file " << fileName;
      return false;
    }
  } else
  {
    LOG(ERROR) << "Unable to open or create file " << fileName;
    return false;
  }

  return true;
}

ConfigVar ConfigReader::toVar() const
{
  // write everything to a ConfigVar, then output to disk
  ConfigVar out;
  out.writeInt( vars.size() );
  map<string, ConfigVar>::const_iterator it;
  for(it = vars.begin(); it != vars.end(); ++it)
  {
    out.writeInt( it->first.size() );
    out.write( (unsigned char*)it->first.data(), it->first.size() );
    out.writeInt( it->second.size() );
    out.write( (unsigned char*)it->second.buffer(), it->second.size() );
  }

  return out;
}

ConfigVar ConfigReader::operator[] ( const std::string &varName ) const
{
  // read only
  map<string, ConfigVar>::const_iterator it = vars.find( varName );
  if( it == vars.end() )
    return ConfigVar();
  else
    return it->second;
}

ConfigVar &ConfigReader::operator[] ( const std::string &varName )
{
    return vars[ varName ];
}