Fix write consistency; separate encrypted directory access to GpgStore class
This commit is contained in:
Jarno Seppänen
parent
529e86621b
commit
727a8bb123
117
gpgfs.py
117
gpgfs.py
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@ -1,56 +1,19 @@
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#!/usr/bin/env python
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from fuse import FUSE, FuseOSError, Operations
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import gnupg # python-gnupg
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import zlib
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import errno
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import stat
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from binascii import hexlify
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import os
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import sys
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import logging
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import struct
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import time
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from cStringIO import StringIO
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import gpgstore
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magic = 'GPGFS1\n'
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log = logging.getLogger(__name__)
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def decrypt(gpg, path):
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try:
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data = file(path).read()
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except IOError, err:
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log.error("read failed: %s: %s", path, str(err))
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raise FuseOSError(err.errno)
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if not data:
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return data
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res = gpg.decrypt(data)
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if not res.ok:
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log.error("decryption failed, %s: %s", res.status, path)
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raise FuseOSError(errno.EIO)
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data = zlib.decompress(res.data)
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log.debug('decrypted %s' % path)
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return data
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def encrypt(gpg, keyid, path, data):
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data = zlib.compress(data, 1)
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res = gpg.encrypt(data, keyid, armor=False)
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if not res.ok:
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log.error("encryption failed (keyid %s), %s: %s",
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keyid, res.status, path)
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raise FuseOSError(errno.EIO)
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try:
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with file(path+'.tmp', 'w') as fd:
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fd.write(res.data)
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os.rename(path+'.tmp', path)
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except IOError, err:
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log.error("write failed: %s: %s", path, str(err))
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raise FuseOSError(err.errno)
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finally:
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try: os.remove(path+'.tmp')
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except: pass
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log.debug('encrypted %s' % path)
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log = logging.getLogger('gpgfs')
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class Entry:
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'''
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@ -64,8 +27,8 @@ class Entry:
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ENT_FILE = 0
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ENT_DIR = 1
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def read_index(gpg, path):
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data = decrypt(gpg, path)
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def read_index(store, path):
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data = store.get(path)
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buf = StringIO(data)
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if buf.read(len(magic)) != magic:
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raise IOError, 'index parse error: %s' % path
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@ -73,13 +36,13 @@ def read_index(gpg, path):
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root = Entry(**read_dict(buf))
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return root
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def write_index(gpg, keyid, path, root):
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def write_index(store, path, root):
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buf = StringIO()
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buf.write(magic)
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header = ''
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write_atom(buf, header)
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write_dict(buf, root)
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encrypt(gpg, keyid, path, buf.getvalue())
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store.put(buf.getvalue(), path=path)
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def write_dict(fd, dct):
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# breadth-first
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@ -167,12 +130,11 @@ class GpgFs(LoggingMixIn, Operations):
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self.encroot = encroot.rstrip('/')
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assert os.path.exists(self.encroot)
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assert os.path.isdir(self.encroot)
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self.keyid = keyid
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#self.cache = cache
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self.gpg = gnupg.GPG()
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self.index_path = self.encroot + '/index'
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if os.path.exists(self.index_path):
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self.root = read_index(self.gpg, self.index_path)
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self.store = gpgstore.GpgStore(self.encroot, keyid)
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self.index_path = 'index'
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if os.path.exists(self.encroot + '/' + self.index_path):
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self.root = read_index(self.store, self.index_path)
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else:
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self.root = Entry(type=ENT_DIR, children={},
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st_mode=0755,
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@ -183,8 +145,8 @@ class GpgFs(LoggingMixIn, Operations):
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self.fd = 0
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self._clear_write_cache()
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def _write_index(self, suffix=''):
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write_index(self.gpg, self.keyid, self.index_path + suffix, self.root)
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def _write_index(self):
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write_index(self.store, self.index_path, self.root)
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def _find(self, path, parent=False):
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assert path.startswith('/')
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@ -229,17 +191,11 @@ class GpgFs(LoggingMixIn, Operations):
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raise FuseOSError(errno.ENOSYS)
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def create(self, path, mode):
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encpath = hexlify(os.urandom(20))
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encpath = encpath[:2] + '/' + encpath[2:]
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dir, path = self._find(path, parent=True)
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if path in dir.children:
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raise FuseOSError(errno.EEXIST)
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encdir = self.encroot + '/' + encpath[:2]
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if not os.path.exists(encdir):
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os.mkdir(encdir, 0755)
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fd = os.open(self.encroot + '/' + encpath,
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os.O_WRONLY | os.O_CREAT, mode & 0777)
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os.close(fd)
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# FIXME mode
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encpath = self.store.put('')
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prev_mtime = dir.st_mtime
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dir.children[path] = Entry(type=ENT_FILE, path=encpath, st_size=0)
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log.debug('new path %s => %s', path, encpath)
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@ -247,7 +203,7 @@ class GpgFs(LoggingMixIn, Operations):
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try:
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self._write_index()
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except:
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try: os.remove(self.encroot + '/' + encpath)
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try: self.store.delete(encpath)
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except: pass
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del dir.children[path]
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dir.st_mtime = prev_mtime
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@ -259,26 +215,29 @@ class GpgFs(LoggingMixIn, Operations):
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if not self.write_dirty:
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log.debug('nothing to flush')
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return 0
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ent = self._find(self.write_path)
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encpath = self.encroot + '/' + ent.path
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buf = ''.join(self.write_buf)
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self.write_buf = [buf]
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encrypt(self.gpg, self.keyid, encpath+'.new', buf)
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ent = self._find(self.write_path)
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prev_size = ent.st_size
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prev_path = ent.path
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ent.st_size = len(buf)
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ent.path = self.store.put(buf)
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try:
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self._write_index(suffix='.new')
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self._write_index()
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except:
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os.remove(encpath+'.new')
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self.store.delete(ent.path)
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ent.st_size = prev_size
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ent.path = prev_path
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raise
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# FIXME renames cannot fail, right?
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os.rename(encpath+'.new', encpath)
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os.rename(self.index_path+'.new', self.index_path)
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self.store.delete(prev_path)
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self.write_dirty = False
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log.debug('flushed %d bytes to %s', len(buf), self.write_path)
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return 0
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def fsync(self, path, datasync, fh):
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self.flush(path, fh)
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return 0
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def getattr(self, path, fh = None):
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ent = self._find(path)
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if ent.type == ENT_DIR:
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@ -324,8 +283,7 @@ class GpgFs(LoggingMixIn, Operations):
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self.flush(path, 0)
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ent = self._find(path)
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assert ent.type == ENT_FILE
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encpath = self.encroot + '/' + ent.path
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data = decrypt(self.gpg, encpath)
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data = self.store.get(ent.path)
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return data[offset:offset + size]
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def readdir(self, path, fh):
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@ -404,25 +362,23 @@ class GpgFs(LoggingMixIn, Operations):
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self.flush(path, 0)
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self._clear_write_cache()
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ent = self._find(path)
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encpath = self.encroot + '/' + ent.path
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if length == 0:
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with open(encpath+'.new', 'w'):
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pass
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buf = ''
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else:
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buf = decrypt(self.gpg, encpath)
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buf = self.store.get(ent.path)
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buf = buf[:length]
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encrypt(self.gpg, self.keyid, encpath+'.new', buf)
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prev_size = ent.st_size
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prev_path = ent.path
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ent.st_size = length
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ent.path = self.store.put(buf)
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try:
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self._write_index(suffix='.new')
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self._write_index()
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except:
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os.remove(ent.path)
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ent.st_size = prev_size
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os.remove(encpath+'.new')
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ent.path = prev_path
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raise
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# FIXME renames cannot fail, right?
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os.rename(encpath+'.new', encpath)
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os.rename(self.index_path+'.new', self.index_path)
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self.store.delete(prev_path)
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def unlink(self, path):
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if self.write_path == path:
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@ -465,10 +421,9 @@ class GpgFs(LoggingMixIn, Operations):
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def write(self, path, data, offset, fh):
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ent = self._find(path)
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encpath = self.encroot + '/' + ent.path
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if path != self.write_path:
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self.flush(self.write_path, None)
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buf = decrypt(self.gpg, encpath)
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buf = self.store.get(ent.path)
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self.write_buf = [buf]
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self.write_len = len(buf)
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self.write_path = path
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@ -0,0 +1,62 @@
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import os
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import gnupg
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from binascii import hexlify
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import zlib
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import errno
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import logging
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log = logging.getLogger('gpgfs')
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class GpgStore(object):
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def __init__(self, encroot, keyid):
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self.encroot = encroot
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self.keyid = keyid
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self.gpg = gnupg.GPG()
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def put(self, data, path=None):
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if not path:
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path = hexlify(os.urandom(20))
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path = path[:2] + '/' + path[2:]
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encdir = self.encroot + '/' + path[:2]
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if not os.path.exists(encdir):
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os.mkdir(encdir, 0755)
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data = zlib.compress(data, 1)
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res = self.gpg.encrypt(data, self.keyid, armor=False)
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if not res.ok:
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log.error("encryption failed (keyid %s), %s: %s",
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self.keyid, res.status, path)
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raise OSError(errno.EIO)
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try:
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with file(self.encroot + '/' + path + '.tmp', 'w') as fd:
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fd.write(res.data)
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os.rename(self.encroot + '/' + path + '.tmp',
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self.encroot + '/' + path)
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except IOError, err:
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log.error("write failed: %s: %s", path, str(err))
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raise OSError(err.errno)
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finally:
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try: os.remove(self.encroot + '/' + path + '.tmp')
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except: pass
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log.debug('encrypted %s' % path)
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return path
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def get(self, path):
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try:
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data = file(self.encroot + '/' + path).read()
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except OSError, err:
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log.error("read failed: %s: %s", path, str(err))
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raise
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if not data:
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return data
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res = self.gpg.decrypt(data)
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if not res.ok:
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log.error("decryption failed, %s: %s", res.status, path)
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raise OSError(errno.EIO)
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data = zlib.decompress(res.data)
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log.debug('decrypted %s' % path)
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return data
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def delete(self, path):
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os.remove(self.encroot + '/' + path)
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log.debug('deleted %s' % path)
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