path: root/FuseArchive/ChunkFile.py

import logging, os, errno, fcntl, fuse, FuseArchive
import FuseArchive.Storage.ZipFile, FuseArchive.Storage.FileSystem
from binascii import hexlify
from FuseArchive.Serializer import Serializer

# These control some of the file output
magic_blocksize = 1024 * 128
# Use a tiny block size to debug writes, so you can use a smaller test file
#magic_blocksize = 1024
chunkstyle = 'fs'

# Memory for dirty blocks, per file (1M)
dirty_size = 1024 * 1024 * 1;
# This is the number of actualy blocks in that size
dirty_flush = int( dirty_size / magic_blocksize )

# This is a cache of open files by inode, to fix the lseek == size problem
# this causes a failure in fsx-linux becuase to to lseek(fd,0,seek_end) it
# apparently does a getattr to find the file length then subtracts the
# offset from that to pass to write or whatever, since the offset is passed
# to write and we don't maintain one internally.  xmp.py also fails this
# test.
dirty_cache = {}

def flag2mode(flags):
    md = {os.O_RDONLY: 'r', os.O_WRONLY: 'w', os.O_RDWR: 'w+'}
    m = md[flags & (os.O_RDONLY | os.O_WRONLY | os.O_RDWR)]

    if flags & os.O_APPEND:
        m = m.replace('w', 'a', 1)

    return m

if chunkstyle == 'fs':
    load_chunk = FuseArchive.Storage.FileSystem.load_chunk
    save_chunk = FuseArchive.Storage.FileSystem.save_chunk
elif chunkstyle == 'zip':
    load_chunk = FuseArchive.Storage.ZipFile.load_chunk
    save_chunk = FuseArchive.Storage.ZipFile.save_chunk
else:
    raise ValueException( 'Invalid chunk style' )

class FuseArchiveStat(fuse.Stat):
    def __init__(self, stat):
        self.st_mode = stat.st_mode
        self.st_ino = stat.st_ino
        self.st_dev = stat.st_dev
        self.st_rdev = stat.st_rdev
        self.st_nlink = stat.st_nlink
        self.st_uid = stat.st_uid
        self.st_gid = stat.st_gid
        self.st_size = stat.st_size
        self.st_atime = stat.st_atime
        self.st_mtime = stat.st_mtime
        self.st_ctime = stat.st_mtime
        self.st_blocks = stat.st_blocks
        self.st_blksize = stat.st_blksize

    def overstat( self, size ):
        self.st_size = size
        # Yeah we shouldn't always just add 1
        self.st_blocks = int( self.st_size / 512 ) + 1

class ChunkFile(object):

    def __init__(self, path, flags, *mode):
        # Inflate the file
        logging.debug( "Init file: " + path )
        self.orig_path = path

        # init rw and offset
        self.rd = False
        self.wr = False
        self.size = 0
        self.modified = False

        # This is the current in-memory chunk and offset in to data[]
        self.chunk_cache = {};
        self.chunk = ''
        self.chunk_index = -1
        self.chunk_modified = False
        self.chunk_size = magic_blocksize
        self.dirty_chunks = 0

        # The chunk table
        self.chunks = []

        # TODO: Better flag handling here?
        if flags & os.O_RDONLY:
            self.rd = True

        if flags & os.O_RDWR:
            self.rd = True
            self.wr = True

        if flags & os.O_WRONLY:
            self.wr = True

        if flags & os.O_APPEND:
            self.wr = True

        if os.path.exists( "./tree" + self.orig_path ):
            preexist = True
        else:
            preexist = False

        # Open the file now and keep the fh around so that cp -a on r/o
        # files works (in the create a read-only file for writing case)
        src = "./tree" + path
        logging.debug( "Saving fh for " + src )
        nflags = os.O_RDWR | os.O_APPEND
        if flags & os.O_CREAT:
            logging.debug( "Adding O_CREAT" )
            nflags = nflags | os.O_CREAT

        self.file = os.fdopen( os.open( src, nflags, *mode ),
            flag2mode( nflags ) )

        if preexist:
            # Read in file info table
            logging.debug( "Unpickling: %s" % self.file )
            # TODO: return an IO error if inflating fails
            try:
                magic = Serializer.loadfh( self.file )
                logging.debug( "Got data: %s" % magic )
                self.size = magic[ 'size' ]
                self.chunks = magic[ 'chunks' ]
                self.chunk_size = magic[ 'chunk_size' ]
            except Exception, e:
                logging.critical( self.orig_path + ": " + str( e ) )
        else:
            if self.wr:
                logging.debug( "File doesn't exist and we're going to write, creating temp empty file" )
                self.modified = True
                self.flush()

        self.direct_io = False
        self.keep_cache = False

        logging.debug( "%s init complete" % self )

    def _load_chunk( self, index ):
        # If the current chunk is the same as the chunk we're loading
        # just return
        logging.debug( "_load_chunk: %d" % index )

        if index == self.chunk_index:
            logging.debug( "Load chunk is same as current chunk, all done" )
            return

        # Save this chunk if modified
        self._save_chunk()

        logging.debug( "Loading chunk %d" % index )
        key = None

        size = len( self.chunks )
        if index >= size:
            logging.debug( "Index doesn't exist" )
        else:
            key = self.chunks[ index ]

        if key:
            if isinstance( key, str ):
                logging.debug( "Found cached dirty page" )
                self.chunk = key
            else:
                logging.debug( "Index: %s" % key )
                self.chunk = load_chunk( key )
        else:
            logging.debug( "No chunk at this index, loading nothing" )
            self.chunk = ''

        logging.debug( "Loaded chunk of length: %d" % len( self.chunk ) )

        self.chunk_index = index
        self.chunk_modified = False

    # This simply puts the chunk data inside our current chunks at chunk_index
    def _save_chunk(self):
        if self.chunk_modified:
            logging.debug( "Saving chunk %d" % self.chunk_index )

            # Make sure we have room for this chunk
            size = len( self.chunks )
            if self.chunk_index >= size:
                self.chunks.extend( [ '' ] * ( self.chunk_index  -size + 1 ) )

            # Increment dirty chunks if we had a key here already
            if isinstance( self.chunks[ self.chunk_index ], list ) or \
                    len( self.chunks[ self.chunk_index ] ) == 0:
                self.dirty_chunks += 1
                logging.debug( "Dirty chunks is now: %d" % self.dirty_chunks )
                logging.debug( "Dirty flush at: %d" % dirty_flush )

            # Save the dirty chunk temporarily in memory
            self.chunks[ self.chunk_index ] = self.chunk

            # Flush if we have too many dirty chunks
            if self.dirty_chunks > dirty_flush:
                self._flush_chunks()

    # This flushes any cached chunks
    def _flush_chunks(self):
        for index in range( len( self.chunks ) ):
            if isinstance( self.chunks[ index ], str ):
                logging.debug( "Flushing chunk at %d" % index )
                key = save_chunk( self.chunks[ index ] )
                self.chunks[ index ] = key
                logging.debug( "Key was %s" % key )
                self.dirty_chunks = 0

    def read(self, length, offset):
        logging.debug( "Reading from %s offset: %d (0x%x) length: %d (0x%d)" %
            ( self.orig_path, offset, offset, length, length ) )

        data_read = 0
        data = ''
        index = int( offset / self.chunk_size )
        rest = offset % self.chunk_size
        is_eof = False

        # Keep reading chunks until we have at least this much data
        while data_read < length and not is_eof:
            logging.debug( "Pulling chunk data: %d" % index )
            self._load_chunk( index )
            if len(self.chunk):
                chunk_remaining = len(self.chunk) - rest
                to_read = chunk_remaining
                data_left = length - data_read
                if data_left < chunk_remaining:
                    to_read = data_left

                logging.debug( "chunk_remaining: %d" % chunk_remaining )
                logging.debug( "data_left: %d" % data_left )
                logging.debug( "data_read: %d" % data_read )
                logging.debug( "rest: %d" % rest )
                logging.debug( "Copying %d bytes" % to_read )

                data += self.chunk[ rest:(rest+to_read) ]
                data_read += to_read
                index += 1
                rest = 0
            else:
                logging.debug( "No more chunk data, bye" )
                is_eof = True

        logging.debug( "Returning %d bytes of data" % len( data ) )
        logging.debug( "Internal count was: %d" % data_read )
        return data

    def write(self, buf, offset):
        if FuseArchive.magic_profiling:
            return len( buf )

        logging.debug( "Writing to %s offset: %d (0x%x) length: %d (0x%x)" %
            ( self.orig_path, offset, offset, len( buf ), len( buf ) ) )

        index = int( offset / self.chunk_size )
        rest = offset % self.chunk_size

        logging.debug( "This chunk falls on index: %d rest: %d" % ( index, rest ) )
        logging.debug( "We have %d chunks" % len( self.chunks ) )
        logging.debug( "File size is: %d" % self.size )

        # If index is higher than the number of blocks we current have it's a seek hole, so we need to extend our blocks out
        # We know these need to essentially be zeroed up to this size since
        if len( self.chunks ) - 1 < index:
            logging.debug( "Not enough chunks %d, need %d, extending" %
                ( len( self.chunks ), index + 1 ) )
            this_index = 0
            while this_index < index:
                self._load_chunk( this_index )
                fill_null = self.chunk_size - len(self.chunk)
                logging.debug( "Filling this chunk with null, bytes: %d" % fill_null )
                self.chunk += "\0" * fill_null
                logging.debug( "Chunk is now: %d bytes" % len( self.chunk) )
                self.chunk_modified = True
                self._save_chunk()
                this_index += 1

        self._load_chunk( index )

        # Now check if this chunk needs to be extended
        if len( self.chunk ) < rest:
            fill_null = rest - len(self.chunk)
            logging.debug( "Filling final chunk with null, bytes: %d" % fill_null )
            self.chunk += "\0" * fill_null
            self.chunk_modified = True
            self._save_chunk()

        buf_offset = 0
        buf_len = len(buf)

        logging.debug( "Length: %d" % buf_len )
        while( buf_offset < buf_len ):
            logging.debug( "Pulling in chunk for writing: %d" % index )
            self._load_chunk( index )
            buf_remain = buf_len - buf_offset
            chunk_remain = self.chunk_size - rest

            logging.debug( "buf_remain: %d" % buf_remain )
            logging.debug( "chunk_remain: %d" % chunk_remain )

            if chunk_remain < buf_remain:
                logging.debug( "Writing %d bytes, buffer boundry" % chunk_remain )
                this_len = chunk_remain
            else:
                logging.debug( "Writing final %d bytes" % buf_remain )
                this_len = buf_remain

            logging.debug( "Bytes to copy: %d" % this_len )
            logging.debug( " buf offset: %d" % buf_offset )
            logging.debug( " chunk offset: %d" % rest )

            if FuseArchive.deep_debug:
                logging.debug( "Pre-Buf: %s" % hexlify(buf) )
                logging.debug( "Pre-Chunk: %s" % hexlify(self.chunk) )

            # Since python doesn't do in-place reassignment like you
            # can with splice() we will reconstruct the data by joining
            # stuff by offsets (first chars to skip, then our joining
            # buf chunk, the everything that would have been after it)
            self.chunk = self.chunk[ :rest ] + \
                buf[ buf_offset:(buf_offset+this_len) ] + \
                self.chunk[ (rest + this_len): ]

            if FuseArchive.deep_debug:
                logging.debug( "Post-Buf: %s" % hexlify(buf) )
                logging.debug( "Post-Chunk: %s" % hexlify(self.chunk) )

            buf_offset += this_len

            # Advance to next block
            rest = 0
            index += 1
            self.chunk_modified = True

        self._save_chunk()
        self.modified = True
        if offset + len(buf) > self.size:
            self.size = offset + len(buf)

        logging.debug( "This chunk size is now: %d" % len( self.chunk ) )
        logging.debug( "File size is now: %d" % self.size )
        logging.debug( "Num Chunks: %d" % len( self.chunks ) )

        # Mark us in the dirty cache
        dirty_cache[ self.orig_path ] = self

        return len(buf)

    # BUG: If you cp -a a file then quickly ls -l sometimes it doesn't show
    # up right?  like wrong size and stuff?
    # Maybe because release doesn't return a fuse message and is async?
    def release(self, flags):
        # Deflate the file
        logging.debug( "Release: " + self.orig_path )
        self.flush()
        self.file.close()

    def _fflush(self):
        if self.wr and self.modified:
            logging.debug( "_fflush!" )
            # Save our main data
            self._save_chunk()

            # And flush any cached chunks
            self._flush_chunks()

            save_size = self.size

            # Figure out our size based on the number of chunks + the
            # len of the final chunk
            numchunks = len( self.chunks )
            if numchunks > 0:
                # Load the last chunk
                logging.debug( "We have %d chunks, calculating size" % numchunks )
                self._load_chunk( numchunks - 1 )
                self.size = ( numchunks - 1 ) * self.chunk_size + \
                    len( self.chunk )
            else:
                logging.debug( "No chunks, setting size to zero" )
                self.size = 0

            # If this assert fails then write/ftruncate failed to set
            # things up right somewhere
            assert save_size == self.size, "Calculated size of " \
                + self.orig_path + " = " + str( self.size ) \
                + " doesn't match internal size " + str( save_size ) \
                + "\nProbably a bug in write or ftruncate!"
            logging.debug( "Size calculated is: %d (0x%x)" % ( self.size, self.size ) )

            Serializer.dumpfh( self.file, {
                'size': self.size,
                'chunks': self.chunks,
                'chunk_size': self.chunk_size
            } )

            # Not dirty anymore
            if self.orig_path in dirty_cache:
                del dirty_cache[ self.orig_path ]


        logging.debug( "_fflush exit" )
        return 1


    # Currently we treat fsync as flush since we don't keep any data
    # hanging around anyway in fh stuff
    def fsync(self, isfsyncfile):
        logging.debug( "fsync " + self.orig_path )
        self._fflush()
        #if isfsyncfile and hasattr(os, 'fdatasync'):
        #    os.fdatasync(self.fd)
        #else:
        #    os.fsync(self.fd)

    def flush(self):
        logging.debug( "flush " + self.orig_path )
        self._fflush()

    def fgetattr(self):
        logging.debug( "Overridding fgetattr" )
        stats = FuseArchiveStat( os.lstat( "./tree" + self.orig_path ) )

        # Fixed in write?
        #if self.modified:
            # We would need to fsync here to recalc size, but don't do
            # it unless modified? otherwise simple getattr will be
            # rewriting a ton of files
        #    print "WARNING: self.modified causes fgetattr to be incorrect!"

        stats.overstat( self.size )
        return stats

    def ftruncate(self, length):
        if not self.wr:
            return errno.IOError

        curr_chunks = len( self.chunks )
        need_chunks = ( length / self.chunk_size )
        extra_bytes = length % self.chunk_size
        logging.debug( "Ftruncate - %d (0x%x)" % ( length, length ) )
        logging.debug( " - self.size: %d" % self.size )
        logging.debug( " - curr_chunks: %d" % curr_chunks )
        logging.debug( " - need_chunks: %d" % need_chunks )
        logging.debug( " - extra_bytes: %d" % extra_bytes )

        if extra_bytes:
            logging.debug( "Need an extra chunk" )
            need_chunks += 1

        self._load_chunk( 0 )

        if length == 0:
            logging.debug( "Creating 0 chunk file" )
            self.chunks = []
            self.chunk = ''
        elif self.size <= length:
            logging.debug( "Need to pad out file, writing/seeking to %d" % length )

            # Just write out null bytes to the length requested, write will do this for us if we specify the offset
            self.write( '', length )
        else:
            logging.debug( "Truncating chunks" )
            while True:
                logging.debug( "Need chunks: %d curr: %d" % ( need_chunks, curr_chunks ) )
                if need_chunks == curr_chunks:
                    break

                logging.debug( "Deleting chunk %d" % self.chunk_index )
                self.chunks.pop()
                curr_chunks = len( self.chunks )

            # Now make sure this chunk is the right size, first load the
            # last chunk
            if len( self.chunks ):
                self._load_chunk( len( self.chunks ) - 1 )
                logging.debug( "Loaded final chunk, len: %d" % len( self.chunk ) )

            # Now truncate this item if needed
            if len( self.chunk ) > extra_bytes:
                logging.debug( "Truncating final chunk to %d" % extra_bytes )
                self.chunk = self.chunk[ :extra_bytes ]
                logging.debug( "Chunk is now: %d bytes" % len( self.chunk ) )

        self.chunk_modified = True
        self.modified = True
        self.size = length
        self._load_chunk( 0 )

        logging.debug( "ftruncate complete" )
        self._fflush()

    def lock(self, cmd, owner, **kw):
        logging.debug( "WARNING: locking unsupported" )
        return 1

        # The code here is much rather just a demonstration of the locking
        # API than something which actually was seen to be useful.

        # Advisory file locking is pretty messy in Unix, and the Python
        # interface to this doesn't make it better.
        # We can't do fcntl(2)/F_GETLK from Python in a platfrom independent
        # way. The following implementation *might* work under Linux. 
        #
        # if cmd == fcntl.F_GETLK:
        #     import struct
        # 
        #     lockdata = struct.pack('hhQQi', kw['l_type'], os.SEEK_SET,
        #                            kw['l_start'], kw['l_len'], kw['l_pid'])
        #     ld2 = fcntl.fcntl(self.fd, fcntl.F_GETLK, lockdata)
        #     flockfields = ('l_type', 'l_whence', 'l_start', 'l_len', 'l_pid')
        #     uld2 = struct.unpack('hhQQi', ld2)
        #     res = {}
        #     for i in xrange(len(uld2)):
        #          res[flockfields[i]] = uld2[i]
        #  
        #     return fuse.Flock(**res)

        # Convert fcntl-ish lock parameters to Python's weird
        # lockf(3)/flock(2) medley locking API...
        op = { fcntl.F_UNLCK : fcntl.LOCK_UN,
                fcntl.F_RDLCK : fcntl.LOCK_SH,
                fcntl.F_WRLCK : fcntl.LOCK_EX }[kw['l_type']]
        if cmd == fcntl.F_GETLK:
            return -errno.EOPNOTSUPP
        elif cmd == fcntl.F_SETLK:
            if op != fcntl.LOCK_UN:
                op |= fcntl.LOCK_NB
        elif cmd == fcntl.F_SETLKW:
            pass
        else:
            return -errno.EINVAL

        fcntl.lockf(self.fd, op, kw['l_start'], kw['l_len'])

    @staticmethod
    def get_dirty_file( path ):
        if path in dirty_cache:
            return( dirty_cache[ path ] )
        else:
            return None