Add rollback code when writing the index file fails
This commit is contained in:
Jarno Seppänen
parent
37c47591ba
commit
6a9ef541ab
141
gpgfs.py
141
gpgfs.py
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@ -18,12 +18,17 @@ magic = 'GPGFS1\n'
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log = logging.getLogger(__name__)
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def decrypt(gpg, path):
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data = file(path).read()
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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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raise IOError, "decryption failed, %s" % path
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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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@ -32,9 +37,19 @@ 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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raise IOError, "encryption failed, keyid %s, path %s" % (keyid, path)
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with file(path, 'w') as fd:
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fd.write(res.data)
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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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class Entry:
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@ -168,8 +183,8 @@ 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):
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write_index(self.gpg, self.keyid, self.index_path, self.root)
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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 _find(self, path, parent=False):
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assert path.startswith('/')
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@ -199,8 +214,13 @@ class GpgFs(LoggingMixIn, Operations):
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mode &= 0777
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ent = self._find(path)
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if ent.type == ENT_DIR:
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prev_mode = ent.st_mode
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ent.st_mode = mode
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self._write_index()
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try:
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self._write_index()
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except:
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ent.st_mode = prev_mode
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raise
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else:
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encpath = self.encroot + '/' + ent.path
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os.chmod(encpath, mode)
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@ -214,16 +234,24 @@ class GpgFs(LoggingMixIn, Operations):
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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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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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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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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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dir.st_mtime = int(time.time())
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self._write_index()
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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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except: pass
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del dir.children[path]
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dir.st_mtime = prev_mtime
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raise
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self.fd += 1
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return self.fd
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@ -234,10 +262,19 @@ class GpgFs(LoggingMixIn, Operations):
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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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encrypt(self.gpg, self.keyid, encpath, buf)
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ent.st_size = len(buf)
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self._write_index()
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self.write_buf = [buf]
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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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ent.st_size = len(buf)
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try:
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self._write_index(suffix='.new')
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except:
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os.remove(encpath+'.new')
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ent.st_size = prev_size
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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.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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@ -266,12 +303,18 @@ class GpgFs(LoggingMixIn, Operations):
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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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prev_mtime = dir.st_mtime
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dir.children[path] = Entry(type=ENT_DIR, children={},
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st_mode=(mode & 0777),
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st_mtime=int(time.time()),
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st_ctime=int(time.time()))
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dir.st_mtime = int(time.time())
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self._write_index()
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try:
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self._write_index()
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except:
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del dir.children[path]
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dir.st_mtime = prev_mtime
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raise
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def open(self, path, flags):
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return 0
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@ -301,15 +344,24 @@ class GpgFs(LoggingMixIn, Operations):
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if old_name not in old_dir.children:
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raise FuseOSError(errno.ENOENT)
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new_dir, new_name = self._find(new, parent=True)
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if new_name in new_dir.children:
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ent = new_dir.children[new_name]
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if ent.type == ENT_FILE:
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os.remove(self.encroot + '/' + ent.path)
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elif ent.children:
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raise FuseOSError(errno.ENOTEMPTY)
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prev_ent = new_dir.children.get(new_name)
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if prev_ent and prev_ent.type == ENT_DIR and prev_ent.children:
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raise FuseOSError(errno.ENOTEMPTY)
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prev_old_mtime = old_dir.st_mtime
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prev_new_mtime = new_dir.st_mtime
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new_dir.children[new_name] = old_dir.children.pop(old_name)
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old_dir.st_mtime = new_dir.st_mtime = int(time.time())
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self._write_index()
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try:
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self._write_index()
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except:
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old_dir.children[old_name] = new_dir.children.pop(new_name)
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if prev_ent:
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new_dir.children[new_name] = prev_ent
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old_dir.st_mtime = prev_old_mtime
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new_dir.st_mtime = prev_new_mtime
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raise
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if prev_ent and prev_ent.type == ENT_FILE:
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os.remove(self.encroot + '/' + prev_ent.path)
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def rmdir(self, path):
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parent, path = self._find(path, parent=True)
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@ -320,9 +372,15 @@ class GpgFs(LoggingMixIn, Operations):
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raise FuseOSError(errno.ENOTDIR)
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if ent.children:
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raise FuseOSError(errno.ENOTEMPTY)
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prev_mtime = parent.st_mtime
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del parent.children[path]
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parent.st_mtime = int(time.time())
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self._write_index()
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try:
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self._write_index()
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except:
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parent.children[path] = ent
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parent.st_mtime = prev_mtime
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raise
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def setxattr(self, path, name, value, options, position = 0):
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raise FuseOSError(errno.ENOSYS)
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@ -339,14 +397,23 @@ class GpgFs(LoggingMixIn, Operations):
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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, 'r+') as f:
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f.truncate(0)
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with open(encpath+'.new', 'w') as f:
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pass
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else:
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buf = decrypt(self.gpg, encpath)
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buf = buf[:length]
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encrypt(self.gpg, self.keyid, encpath, buf)
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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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ent.st_size = length
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self._write_index()
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try:
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self._write_index(suffix='.new')
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except:
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ent.st_size = prev_size
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os.remove(encpath+'.new')
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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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def unlink(self, path):
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if self.write_path == path:
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@ -355,20 +422,32 @@ class GpgFs(LoggingMixIn, Operations):
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dir, name = self._find(path, parent=True)
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if name not in dir.children:
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raise FuseOSError(errno.ENOENT)
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encpath = self.encroot + '/' + dir.children[name].path
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os.remove(encpath)
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ent = dir.children[name]
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encpath = self.encroot + '/' + ent.path
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del dir.children[name]
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prev_mtime = dir.st_mtime
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dir.st_mtime = int(time.time())
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self._write_index()
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try:
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self._write_index()
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except:
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dir.children[name] = ent
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dir.st_mtime = prev_mtime
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raise
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os.remove(encpath)
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def utimens(self, path, times = None):
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ent = self._find(path)
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if ent.type == ENT_DIR:
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prev_mtime = ent.st_mtime
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if times is None:
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ent.st_mtime = int(time.time())
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else:
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ent.st_mtime = times[1]
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self._write_index()
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try:
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self._write_index()
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except:
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ent.st_mtime = prev_mtime
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raise
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else:
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# flush may mess with mtime
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self.flush(path, 0)
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