File.cpp

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/*
 Copyright (c) 2008-2010 TrueCrypt Developers Association. All rights reserved.

 Governed by the TrueCrypt License 3.0 the full text of which is contained in
 the file License.txt included in TrueCrypt binary and source code distribution
 packages.
*/

#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <utime.h>

#ifdef TC_LINUX
#include <sys/mount.h>
#endif

#ifdef TC_BSD
#include <sys/disk.h>
#endif

#ifdef TC_SOLARIS
#include <stropts.h>
#include <sys/dkio.h>
#endif

#include <sys/file.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "Platform/File.h"
#include "Platform/TextReader.h"

namespace TrueCrypt
{
#if 0
#   define TC_TRACE_FILE_OPERATIONS

    static void TraceFileOperation (int fileHandle, FilePath filePath, bool write, uint64 length, int64 position = -1)
    {
        string path = filePath;
        if (path.empty() || path.find ("truecrypt_aux_mnt") != string::npos)
            return;

        stringstream s;
        s << path << ": " << (write ? "W " : "R ") << (position == -1 ? lseek (fileHandle, 0, SEEK_CUR) : position) << " (" << length << ")";
        SystemLog::WriteError (s.str());
    }
#endif

    void File::Close ()
    {
        if_debug (ValidateState());

        if (!SharedHandle)
        {
            close (FileHandle);
            FileIsOpen = false;

            if ((mFileOpenFlags & File::PreserveTimestamps) && Path.IsFile())
            {
                struct utimbuf u;
                u.actime = AccTime;
                u.modtime = ModTime;

                try
                {
                    throw_sys_sub_if (utime (string (Path).c_str(), &u) == -1, wstring (Path));
                }
                catch (...) // Suppress errors to allow using read-only files
                {
#ifdef DEBUG 
                    throw;
#endif
                }
            }
        }
    }

    void File::Delete ()
    {
        Close();
        Path.Delete();
    }


    void File::Flush () const
    {
        if_debug (ValidateState());
        throw_sys_sub_if (fsync (FileHandle) != 0, wstring (Path));
    }

    uint32 File::GetDeviceSectorSize () const
    {
        if (Path.IsDevice())
        {
#ifdef TC_LINUX
            int blockSize;
            throw_sys_sub_if (ioctl (FileHandle, BLKSSZGET, &blockSize) == -1, wstring (Path));
            return blockSize;

#elif defined (TC_MACOSX)
            uint32 blockSize;
            throw_sys_sub_if (ioctl (FileHandle, DKIOCGETBLOCKSIZE, &blockSize) == -1, wstring (Path));
            return blockSize;

#elif defined (TC_FREEBSD)
            u_int sectorSize;
            throw_sys_sub_if (ioctl (FileHandle, DIOCGSECTORSIZE, &sectorSize) == -1, wstring (Path));
            return (uint32) sectorSize;

#elif defined (TC_SOLARIS)
            struct dk_minfo mediaInfo;
            throw_sys_sub_if (ioctl (FileHandle, DKIOCGMEDIAINFO, &mediaInfo) == -1, wstring (Path));
            return mediaInfo.dki_lbsize;

#else
#   error GetDeviceSectorSize()
#endif
        }
        else
            throw ParameterIncorrect (SRC_POS);
    }

    uint64 File::GetPartitionDeviceStartOffset () const
    {
#ifdef TC_LINUX

        // HDIO_GETGEO ioctl is limited by the size of long
        TextReader tr ("/sys/block/" + string (Path.ToHostDriveOfPartition().ToBaseName()) + "/" + string (Path.ToBaseName()) + "/start");
        
        string line;
        tr.ReadLine (line);
        return StringConverter::ToUInt64 (line) * GetDeviceSectorSize();

#elif defined (TC_MACOSX)

#ifndef DKIOCGETBASE
#   define DKIOCGETBASE _IOR('d', 73, uint64)
#endif
        uint64 offset;
        throw_sys_sub_if (ioctl (FileHandle, DKIOCGETBASE, &offset) == -1, wstring (Path));
        return offset;

#elif defined (TC_SOLARIS)

        struct extpart_info partInfo;
        throw_sys_sub_if (ioctl (FileHandle, DKIOCEXTPARTINFO, &partInfo) == -1, wstring (Path));
        return partInfo.p_start * GetDeviceSectorSize();

#else
        throw NotImplemented (SRC_POS);
#endif
    }

    uint64 File::Length () const
    {
        if_debug (ValidateState());

        // BSD does not support seeking to the end of a device
#ifdef TC_BSD
        if (Path.IsBlockDevice() || Path.IsCharacterDevice())
        {
#   ifdef TC_MACOSX
            uint32 blockSize;
            uint64 blockCount;
            throw_sys_sub_if (ioctl (FileHandle, DKIOCGETBLOCKSIZE, &blockSize) == -1, wstring (Path));
            throw_sys_sub_if (ioctl (FileHandle, DKIOCGETBLOCKCOUNT, &blockCount) == -1, wstring (Path));
            return blockCount * blockSize;
#   else
            uint64 mediaSize;
            throw_sys_sub_if (ioctl (FileHandle, DIOCGMEDIASIZE, &mediaSize) == -1, wstring (Path));
            return mediaSize;
#   endif
        }
#endif
        off_t current = lseek (FileHandle, 0, SEEK_CUR);
        throw_sys_sub_if (current == -1, wstring (Path));
        SeekEnd (0);
        uint64 length = lseek (FileHandle, 0, SEEK_CUR);
        SeekAt (current);
        return length;
    }

    void File::Open (const FilePath &path, FileOpenMode mode, FileShareMode shareMode, FileOpenFlags flags)
    {
#ifdef TC_LINUX
        int sysFlags = O_LARGEFILE;
#else
        int sysFlags = 0;
#endif

        switch (mode)
        {
        case CreateReadWrite:
            sysFlags |= O_CREAT | O_TRUNC | O_RDWR;
            break;
                
        case CreateWrite:
            sysFlags |= O_CREAT | O_TRUNC | O_WRONLY;
            break;

        case OpenRead:
            sysFlags |= O_RDONLY;
            break;

        case OpenWrite:
            sysFlags |= O_WRONLY;
            break;

        case OpenReadWrite:
            sysFlags |= O_RDWR;
            break;

        default:
            throw ParameterIncorrect (SRC_POS);
        }

        if ((flags & File::PreserveTimestamps) && path.IsFile())
        {
            struct stat statData;
            throw_sys_sub_if (stat (string (path).c_str(), &statData) == -1, wstring (path));
            AccTime = statData.st_atime;
            ModTime = statData.st_mtime;
        }

        FileHandle = open (string (path).c_str(), sysFlags, S_IRUSR | S_IWUSR);
        throw_sys_sub_if (FileHandle == -1, wstring (path));

#if 0 // File locking is disabled to avoid remote filesystem locking issues
        try
        {
            struct flock fl;
            memset (&fl, 0, sizeof (fl));
            fl.l_whence = SEEK_SET;
            fl.l_start = 0;
            fl.l_len = 0;

            switch (shareMode)
            {
            case ShareNone:
                fl.l_type = F_WRLCK;
                if (fcntl (FileHandle, F_SETLK, &fl) == -1)
                    throw_sys_sub_if (errno == EAGAIN || errno == EACCES, wstring (path));
                break;

            case ShareRead:
                fl.l_type = F_RDLCK;
                if (fcntl (FileHandle, F_SETLK, &fl) == -1)
                    throw_sys_sub_if (errno == EAGAIN || errno == EACCES, wstring (path));
                break;

            case ShareReadWrite:
                fl.l_type = (mode == OpenRead ? F_RDLCK : F_WRLCK);
                if (fcntl (FileHandle, F_GETLK, &fl) != -1 && fl.l_type != F_UNLCK)
                {
                    errno = EAGAIN;
                    throw SystemException (SRC_POS, wstring (path));
                }
                break;
            
            case ShareReadWriteIgnoreLock:
                break;

            default:
                throw ParameterIncorrect (SRC_POS);
            }
        }
        catch (...)
        {
            close (FileHandle);
            throw;
        }
#endif // 0

        Path = path;
        mFileOpenFlags = flags;
        FileIsOpen = true;
    }

    uint64 File::Read (const BufferPtr &buffer) const
    {
        if_debug (ValidateState());

#ifdef TC_TRACE_FILE_OPERATIONS
        TraceFileOperation (FileHandle, Path, false, buffer.Size());
#endif
        ssize_t bytesRead = read (FileHandle, buffer, buffer.Size());
        throw_sys_sub_if (bytesRead == -1, wstring (Path));

        return bytesRead;
    }

    uint64 File::ReadAt (const BufferPtr &buffer, uint64 position) const
    {
        if_debug (ValidateState());

#ifdef TC_TRACE_FILE_OPERATIONS
        TraceFileOperation (FileHandle, Path, false, buffer.Size(), position);
#endif
        ssize_t bytesRead = pread (FileHandle, buffer, buffer.Size(), position);
        throw_sys_sub_if (bytesRead == -1, wstring (Path));

        return bytesRead;
    }

    void File::SeekAt (uint64 position) const
    {
        if_debug (ValidateState());
        throw_sys_sub_if (lseek (FileHandle, position, SEEK_SET) == -1, wstring (Path));
    }

    void File::SeekEnd (int offset) const
    {
        if_debug (ValidateState());

        // BSD does not support seeking to the end of a device
#ifdef TC_BSD
        if (Path.IsBlockDevice() || Path.IsCharacterDevice())
        {
            SeekAt (Length() + offset);
            return;
        }
#endif

        throw_sys_sub_if (lseek (FileHandle, offset, SEEK_END) == -1, wstring (Path));
    }

    void File::Write (const ConstBufferPtr &buffer) const
    {
        if_debug (ValidateState());

#ifdef TC_TRACE_FILE_OPERATIONS
        TraceFileOperation (FileHandle, Path, true, buffer.Size());
#endif
        throw_sys_sub_if (write (FileHandle, buffer, buffer.Size()) != (ssize_t) buffer.Size(), wstring (Path));
    }
    
    void File::WriteAt (const ConstBufferPtr &buffer, uint64 position) const
    {
        if_debug (ValidateState());

#ifdef TC_TRACE_FILE_OPERATIONS
        TraceFileOperation (FileHandle, Path, true, buffer.Size(), position);
#endif
        throw_sys_sub_if (pwrite (FileHandle, buffer, buffer.Size(), position) != (ssize_t) buffer.Size(), wstring (Path));
    }
}