aboutsummaryrefslogtreecommitdiffstats
path: root/fusearchive.py
blob: b1ebc367b93ca471d49c51acaa6d110c9c1fc2ee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
#!/usr/bin/env python

#    Copyright (C) 2001  Jeff Epler  <jepler@unpythonic.dhs.org>
#    Copyright (C) 2006  Csaba Henk  <csaba.henk@creo.hu>
#    Copyright (C) 2009  Steve Slaven  <bpk@hoopajoo.net>
#
#    This program can be distributed under the terms of the GNU LGPL.
#    See the file COPYING.
#

import os, sys, shutil, fcntl, fuse, re
import tempfile, sha, pickle, gzip
from errno import *
from stat import *
from fuse import Fuse

import pdb

if not hasattr(fuse, '__version__'):
    raise RuntimeError, \
        "your fuse-py doesn't know of fuse.__version__, probably it's too old."

fuse.fuse_python_api = (0, 2)

fuse.feature_assert('stateful_files', 'has_init')

magic_blocksize = 1024 * 32
magic_depth = 5
debug_level = 2

def dmsg(level,message):
    if level <= debug_level:
        print str(level) + ": " + message

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

# Inflate a file, src is a packed file, dest is where the unpacked file
# should go
# we assume our chunks are in storage/
def inflate( src, dest ):
    dmsg( 1, "inflate!" )

    out = open( dest, "w" )

    dmsg( 2, "Unpickling: " + src )
    # TODO: return an IO error if inflating fails
    inp = gzip.open( src, "r" )
    magic = pickle.load( inp )
    inp.close()
    dmsg( 2, "Got data: " + str( magic ) )

    #pdb.set_trace()

    # Now unserialize the chunks back in to a file
    for key in magic[ 'data' ]:
        ( hash, seq ) = key

        chars = list( hash )
        dmsg( 4, chars )

        # Todo: make a digest -> path function to share with deflate
        hexdigest = ''.join( [ "%02x" % ord( x ) for x in chars ] );
        subparts = [ "%02x" % ord( x ) for x in chars[ :magic_depth ] ]
        subpath = '/'.join( subparts );
        dmsg( 3, "Subpath: " + subpath )

        subpath += "/" + hexdigest + "_" + str( seq );

        dmsg( 3, "Chunk path: " + subpath )

        if os.path.exists( "./storage/" + subpath ):
            dmsg( 3, "Exporting chunk" )
            readchunk = gzip.open( "./storage/" + subpath )
            out.write( readchunk.read() )
            readchunk.close()
        else:
            raise IOError

    dmsg( 2, "File inflated" )
    out.close()

# TODO: deflate only if the file has been modified

# Deflate a file, src is the unpacked file, dest is where we want to pack
# to, and we assume storage/ is where chunks are stored
def deflate( src, dest ):
    dmsg( 2, "deflate!" )
    inp = open( src, "r" )

    hashs = [];
    # This is retarded:
    # http://groups.google.com/group/comp.lang.python/browse_thread/thread/ed25388487b3ac7b
    #
    # Why can't I just do:
    # while( chunk = inp.read( magic_blocksize ) ):
    # I though python was supposed to be easier! :(

    while True:
        chunk = inp.read( magic_blocksize )
        if len( chunk ) == 0:
            break

        # Save this hash string, similar to the backuppc algo
        digest = sha.new( str(len(chunk)) + chunk ).digest()

        # Write out our chunk
        chars = list( digest )
        dmsg( 4, chars )

        # We make the hexdigest here, yeah we could just call hexdigest()
        # but we need to essentially do this same thing to reassemble the
        # file anyway
        hexdigest = ''.join( [ "%02x" % ord( x ) for x in chars ] );

        # Subparts just needs the first N chars
        subparts = [ "%02x" % ord( x ) for x in chars[ :magic_depth ] ]

        dmsg( 4, subparts )
        subpath = '/'.join( subparts );
        dmsg( 3, "Subpath: " + subpath )

        # Make sure this sub path exists
        nextpart = "./storage"
        for part in subparts:
            nextpart += "/" + part
            if not os.path.exists( nextpart ):
                dmsg( 3, "Creating subdir: " + nextpart )
                os.mkdir( nextpart )

        # Find a chunk slot
        sub = 0
        while True:
            checkpath = "./storage/" + subpath + "/" + hexdigest + "_" + str( sub )
            dmsg( 3, "Checking: " + checkpath )
            if os.path.exists( checkpath ):
                # Check if this is our data
                verify = gzip.open( checkpath, "r" )
                verify_contents = verify.read()
                verify.close()

                if verify_contents == chunk:
                    dmsg( 2, "Found existing block" )
                    break
                else:
                    dmsg( 2, "Block exists but is not the same" )
                    sub += 1
            else:
                # We found a spot, dump our data here
                dmsg( 2, "No block here, creating new block" )
                savechunk = gzip.open( checkpath, "w" )
                savechunk.write( chunk )
                savechunk.close
                break

        dmsg( 2, "Got chunk slot: " + str( sub ) )
        hashs.append( [ digest, sub ] )

    inp.close()

    out = gzip.open( dest, "w" )
    pickle.dump( {
        'stat': os.stat( src ),
        'data': hashs
    }, out )
    out.close()

class FuseArchiveStat(fuse.Stat):
    def __init__(self, stat, overstat):
        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 = overstat.st_size
        self.st_atime = stat.st_atime
        self.st_mtime = stat.st_mtime
        self.st_ctime = stat.st_mtime
        # Yeah we shouldn't always just add 1
        self.st_blocks = int( self.st_size / 512 ) + 1
        self.st_blksize = stat.st_blksize

class FuseArchive(Fuse):

    def __init__(self, *args, **kw):

        Fuse.__init__(self, *args, **kw)
        self.root = None

    # Fix getattr and fgetattr to?
    def getattr(self, path):
        treefile = "./tree" + path
        stats = os.lstat( treefile )

        if os.path.isfile( treefile ):
            dmsg( 3, "Reading file to get size: " + path )

            #pdb.set_trace()

            # Override size
            inp = gzip.open( treefile )
            magic = pickle.load( inp )
            inp.close()

            dmsg( 3, "Overridding getattr" )
            stats = FuseArchiveStat( stats, magic[ 'stat' ] )

        return stats

    def readlink(self, path):
        return os.readlink("./tree" + path)

    def readdir(self, path, offset):
        for e in os.listdir("./tree" + path):
            yield fuse.Direntry(e)

    def unlink(self, path):
        os.unlink("./tree" + path)

    def rmdir(self, path):
        os.rmdir("./tree" + path)

    def symlink(self, path, path1):
        os.symlink(path, "./tree" + path1)

    def rename(self, path, path1):
        os.rename("./tree" + path, "./tree" + path1)

    def link(self, path, path1):
        os.link("./tree" + path, "./tree" + path1)

    def chmod(self, path, mode):
        os.chmod("./tree" + path, mode)

    def chown(self, path, user, group):
        os.chown("./tree" + path, user, group)

    def truncate(self, path, len):
        # Truncate using the ftruncate on the file
        dmsg( 2, "Using FuseArchiveFile to truncate " + path + " to " + str(len) )
        f = self.FuseArchiveFile( path, os.O_APPEND, 0 )
        f.ftruncate(len)
        f.release( 0 )

    def mknod(self, path, mode, dev):
        os.mknod("./tree" + path, mode, dev)

    def mkdir(self, path, mode):
        os.mkdir("./tree" + path, mode)

    def utime(self, path, times):
        os.utime("./tree" + path, times)

#    The following utimens method would do the same as the above utime method.
#    We can't make it better though as the Python stdlib doesn't know of
#    subsecond preciseness in acces/modify times.
#  
#    def utimens(self, path, ts_acc, ts_mod):
#      os.utime("." + path, (ts_acc.tv_sec, ts_mod.tv_sec))

    def access(self, path, mode):
        if not os.access("./tree" + path, mode):
            return -EACCES

#    This is how we could add stub extended attribute handlers...
#    (We can't have ones which aptly delegate requests to the underlying fs
#    because Python lacks a standard xattr interface.)
#
#    def getxattr(self, path, name, size):
#        val = name.swapcase() + '@' + path
#        if size == 0:
#            # We are asked for size of the value.
#            return len(val)
#        return val
#
#    def listxattr(self, path, size):
#        # We use the "user" namespace to please XFS utils
#        aa = ["user." + a for a in ("foo", "bar")]
#        if size == 0:
#            # We are asked for size of the attr list, ie. joint size of attrs
#            # plus null separators.
#            return len("".join(aa)) + len(aa)
#        return aa

    def statfs(self):
        """
        Should return an object with statvfs attributes (f_bsize, f_frsize...).
        Eg., the return value of os.statvfs() is such a thing (since py 2.2).
        If you are not reusing an existing statvfs object, start with
        fuse.StatVFS(), and define the attributes.

        To provide usable information (ie., you want sensible df(1)
        output, you are suggested to specify the following attributes:

            - f_bsize - preferred size of file blocks, in bytes
            - f_frsize - fundamental size of file blcoks, in bytes
                [if you have no idea, use the same as blocksize]
            - f_blocks - total number of blocks in the filesystem
            - f_bfree - number of free blocks
            - f_files - total number of file inodes
            - f_ffree - nunber of free file inodes
        """

        return os.statvfs(".")

    def fsinit(self):
        os.chdir(self.root)

    class FuseArchiveFile(object):

        def __init__(self, path, flags, *mode):
            # Inflate the file
            dmsg( 2, "Init file: " + path )
            self.orig_path = path;
            ( fdnum, self.tmp_name ) = tempfile.mkstemp();
            #os.close( fdnum );

            if os.path.exists( "./tree" + self.orig_path ):
                inflate( "./tree" + path, self.tmp_name )
            else:
                if re.match( '(a|w)', flag2mode( flags ) ):
                    dmsg( 2, "File doesn't exist and we're going to write, creating temp empty file" )
                    deflate( "/dev/null", "./tree" + path )

            dmsg( 2, "Shadow file: " + self.tmp_name + " for " + self.orig_path )
            dmsg( 2, "Going to open shadow file with flags: " + str(flags) + " mode " + str(mode) )
            # pdb.set_trace()
            dmsg( 2, "Flag2mode is: " + str( flag2mode( flags ) ) )

            # Just use the fdnum they gave us instead of reopening it,
            # since that might fail
            # fdnum = os.open( self.tmp_name, flags, *mode )
            #print "Got fdnum: " + str(fdnum)
            self.file = os.fdopen( fdnum, flag2mode( flags ) )
            dmsg( 2, "Open" )

            self.fd = self.file.fileno()

            self.direct_io = False
            self.keep_cache = False

            self.modified = False

            dmsg( 2, str(self) + " init complete" )

        def read(self, length, offset):
            dmsg( 2, "Reading from " + self.orig_path )
            self.file.seek(offset)
            return self.file.read(length)

        def write(self, buf, offset):
            dmsg( 2, "Writing to " + self.orig_path )
            self.file.seek(offset)
            self.file.write(buf)
            self.modified = True
            return len(buf)

        def release(self, flags):
            # Deflate the file
            dmsg( 2, "Release: " + self.orig_path )
            self.file.close()

            if self.modified:
                dmsg( 2, "Copying working file back to storage: " + \
                    self.tmp_name + " -> " + self.orig_path )

                #pdb.set_trace()
                deflate( self.tmp_name, "./tree" + self.orig_path )
            else:
                dmsg( 2, "File not modified, not copying back" )

            dmsg( 2, "Deleting old file: " + self.tmp_name )
            os.unlink( self.tmp_name );

        def _fflush(self):
            if 'w' in self.file.mode or 'a' in self.file.mode:
                self.file.flush()

        def fsync(self, isfsyncfile):
            self._fflush()
            if isfsyncfile and hasattr(os, 'fdatasync'):
                os.fdatasync(self.fd)
            else:
                os.fsync(self.fd)

        def flush(self):
            self._fflush()
            # cf. xmp_flush() in fusexmp_fh.c
            os.close(os.dup(self.fd))

        def fgetattr(self):
            return os.fstat(self.fd)

        def ftruncate(self, len):
            self.modified = True
            self.file.truncate(len)

        def lock(self, cmd, owner, **kw):
            # 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 -EOPNOTSUPP
            elif cmd == fcntl.F_SETLK:
                if op != fcntl.LOCK_UN:
                    op |= fcntl.LOCK_NB
            elif cmd == fcntl.F_SETLKW:
                pass
            else:
                return -EINVAL

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


    def main(self, *a, **kw):

        self.file_class = self.FuseArchiveFile

        # This is where fragments go
        if not os.path.exists( 'storage' ):
            os.mkdir( 'storage' )

        # This is where the real files exist
        if not os.path.exists( 'tree' ):
            os.mkdir( 'tree' )

        return Fuse.main(self, *a, **kw)


def main():

    usage = """
Userspace nullfs-alike: mirror the filesystem tree from some point on.

""" + Fuse.fusage

    server = FuseArchive(version="%prog " + fuse.__version__,
                 usage=usage,
                 dash_s_do='setsingle')

    server.multithreaded = False

    server.parse(values=server, errex=1)

    if len(server.parser.largs) != 2:
        print "Usage: " + sys.argv[0] + " storageDirectory mountDirectory"
        sys.exit(1)

    server.root = server.parser.largs[0]

    try:
        if server.fuse_args.mount_expected():
            os.chdir(server.root)
    except OSError:
        print >> sys.stderr, "can't enter root of underlying filesystem"
        sys.exit(1)

    server.main()


if __name__ == '__main__':
    main()