encfs/encfs/Context.cpp

/*****************************************************************************
 * Author:   Valient Gough <vgough@pobox.com>
 *
 *****************************************************************************
 * Copyright (c) 2007, Valient Gough
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "FileNode.h"
#include "Context.h"
#include "Mutex.h"
#include "FileUtils.h"

#include <rlog/rlog.h>

using namespace rel;
using namespace rlog;

EncFS_Context::EncFS_Context()
{ 
    pthread_cond_init( &wakeupCond, 0 );
    pthread_mutex_init( &wakeupMutex, 0 );
    pthread_mutex_init( &contextMutex, 0 );

    usageCount = 0;
}

EncFS_Context::~EncFS_Context()
{
    pthread_mutex_destroy( &contextMutex );
    pthread_mutex_destroy( &wakeupMutex );
    pthread_cond_destroy( &wakeupCond );

    // release all entries from map
    openFiles.clear();
}

shared_ptr<DirNode> EncFS_Context::getRoot(int *errCode)
{
    shared_ptr<DirNode> ret;
    do
    {
	{
	    Lock lock( contextMutex );
	    ret = root;
	    ++usageCount;
	}

	if(!ret)
	{
	    int res = remountFS( this );
	    if(res != 0)
	    {
		*errCode = res;
		break;
	    }
	}
    } while(!ret);

    return ret;
}

void EncFS_Context::setRoot(const shared_ptr<DirNode> &r)
{
    Lock lock( contextMutex );

    root = r;
    if(r)
	rootCipherDir = r->rootDirectory();
}

bool EncFS_Context::isMounted()
{
    return root;
}

int EncFS_Context::getAndResetUsageCounter()
{
    Lock lock( contextMutex );

    int count = usageCount;
    usageCount = 0;

    return count;
}

int EncFS_Context::openFileCount() const
{
    Lock lock( contextMutex );

    return openFiles.size();
}

shared_ptr<FileNode> EncFS_Context::lookupNode(const char *path)
{
    Lock lock( contextMutex );

    FileMap::iterator it = openFiles.find( std::string(path) );
    if(it != openFiles.end())
    {
	rInfo("found existing node for %s", path);
	// all the items in the set point to the same node.. so just use the
	// first
	return (*it->second.begin())->node;
    } else
    {
	rInfo("no node found for %s", path);
	return shared_ptr<FileNode>();
    }
}

void EncFS_Context::renameNode(const char *from, const char *to)
{
    Lock lock( contextMutex );

    FileMap::iterator it = openFiles.find( std::string(from) );
    if(it != openFiles.end())
    {
	std::set<Placeholder *> val = it->second;
	openFiles.erase(it);
	openFiles[ std::string(to) ] = val;
    }
}

shared_ptr<FileNode> EncFS_Context::getNode(void *pl)
{
    Placeholder *ph = (Placeholder*)pl;
    return ph->node;
}

void *EncFS_Context::putNode(const char *path, 
	const boost::shared_ptr<FileNode> &node)
{
    Lock lock( contextMutex );
    Placeholder *pl = new Placeholder( node );
    openFiles[ std::string(path) ].insert(pl);
	
    rInfo("added open node record for %s", path);

    return (void *)pl;
}

void EncFS_Context::eraseNode(const char *path, void *pl)
{
    Lock lock( contextMutex );

    Placeholder *ph = (Placeholder *)pl;

    FileMap::iterator it = openFiles.find( std::string(path) );
    rAssert(it != openFiles.end());
    
    int rmCount = it->second.erase( ph );

    rAssert(rmCount == 1);

    rInfo("released open node record for %s", path);
    // if no more references to this file, remove the record all together
    if(it->second.empty())
    {
	rInfo("last open node closed for %s", path);
	// attempts to make use of shallow copy to clear memory used to hold
	// unencrypted filenames.. not sure this does any good..
	std::string storedName = it->first;
	openFiles.erase( it );
	storedName.assign( storedName.length(), '\0' );
    }

    delete ph;
}