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flatfs.py
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flatfs.py
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#!/usr/bin/env python
from __future__ import with_statement
import os
from stat import S_IFDIR
import sys
import errno
from time import time
from key_val_store import HandleStore
from key_val_store import hash_path
from fuse import FUSE, FuseOSError, Operations
def _split_path(path):
path_split = os.path.split(path[1:])
return path_split[0], path_split[1]
# noinspection PyNoneFunctionAssignment,PyMethodMayBeStatic
class FlatFS(Operations):
def __init__(self, root, mount_point):
self.root = root
self.mount_point = mount_point
db_path = self.root + '/.store.db'
st_dict = self._get_st_dict(os.lstat(self.root))
self.gid = st_dict['st_gid']
self.uid = st_dict['st_uid']
stv = self._get_st_dict(os.lstat(self.root))
self.store = HandleStore(db_path, stv)
handle = self._get_handle_path('/')
if handle is None:
handle = (hash_path('/'), '/', None, 1, stv, None)
self.store.put(hash_path('/'), handle)
def init(self, path):
super(FlatFS, self).init(path)
def __del__(self):
del self.store
# Helpers
# =======
def _full_path(self, partial):
path = self._get_full_path_hash(hash_path(partial))
return path
def _full_path_handle(self, handle):
return os.path.join(self.root, handle[0])
def _get_full_path_hash(self, _hash_path):
path = os.path.join(self.root, _hash_path)
return path
def _is_dir(self, path):
handle = self._get_handle_path(path)
return self._is_dir_handle(handle)
def _is_dir_handle(self, handle):
return handle is not None and handle[3]
def _get_handle_path(self, path):
return self._get_handle_hash(hash_path(path))
def _get_handle_hash(self, path_hash):
return self.store.get(path_hash)
def _list_dir(self, path):
return self.store.get("l_" + hash_path(path))
def _copy_handle(self, handle, key=None, name=None, stv=None):
if key is None:
key = handle[0]
if name is None:
name = handle[1]
if stv is None:
stv = handle[4]
return key, name, handle[2], handle[3], stv, handle[5]
def _create_handle(self, path, is_dir, dir_stv=None, link_path=None):
dir_flag = 0
if is_dir:
dir_flag = 1
parent, name = _split_path(path)
handle = (hash_path(path), name, parent, dir_flag, dir_stv, link_path)
self.store.put(handle[0], handle)
if is_dir:
self.store.put("l_" + handle[0], [])
parent_dir_key = "l_" + hash_path("/" + handle[2])
_dir = self.store.get(parent_dir_key)
_dir.append(handle[1])
self.store.put(parent_dir_key, _dir)
return handle
def _rename_handle(self, old, new):
parent, name = _split_path(new)
self._remove_handle(new)
parent, old_name = os.path.split(old)
parent_hash = hash_path(parent)
parent_l = self.store.get("l_" + parent_hash)
parent_l.remove(old_name)
parent_l.append(name)
self.store.put("l_" + parent_hash, parent_l)
handle = self._remove_handle(old)
handle = self._copy_handle(handle, key=hash_path(new), name=name)
self.store.put(handle[0], handle)
def _update_dir_stv(self, handle, new_stv):
handle = self._copy_handle(handle, stv=new_stv)
self.store.put(handle[0], handle)
def _remove_handle(self, path):
_hash_path = hash_path(path)
handle = self.store.remove(_hash_path)
if handle is not None:
parent, name = os.path.split(path)
if handle[3] == 1:
self.store.remove('l_' + _hash_path)
parent_hash = hash_path(parent)
parent_l = self.store.get("l_" + parent_hash)
if name in parent_l:
parent_l.remove(name)
self.store.put("l_" + parent_hash, parent_l)
return handle
def _get_dir_stv(self, handle):
return handle[4]
def _create_new_dir_st(self, mode):
return dict(st_mode=(S_IFDIR | mode), st_nlink=2, st_size=0, st_ctime=time(), st_mtime=time(), st_atime=time(),
st_gid=self.gid, st_uid=self.uid)
def _get_st_dict(self, st):
return dict((key, getattr(st, key)) for key in
('st_atime', 'st_ctime', 'st_gid', 'st_mode', 'st_mtime', 'st_nlink', 'st_size', 'st_uid'))
# Filesystem methods
# ==================
def access(self, path, mode):
if not os.access(self.root, mode):
raise FuseOSError(errno.EACCES)
def chmod(self, path, mode):
handle = self._get_handle_path(path)
if self._is_dir_handle(handle):
stv = self._get_dir_stv(handle)
stv['st_mode'] &= 0770000
stv['st_mode'] |= mode
self._update_dir_stv(handle, stv)
return 0
full_path = self._full_path(path)
return os.chmod(full_path, mode)
def chown(self, path, uid, gid):
handle = self._get_handle_path(path)
if self._is_dir_handle(handle):
stv = self._get_dir_stv(handle)
stv['st_uid'] = uid
stv['st_gid'] = gid
self._update_dir_stv(handle, stv)
return 0
full_path = self._full_path(path)
return os.chown(full_path, uid, gid)
def getattr(self, path, fh=None):
handle = self._get_handle_path(path)
if self._is_dir_handle(handle):
return self._get_dir_stv(handle)
else:
st = os.lstat(self._full_path(path))
return self._get_st_dict(st)
def readdir(self, path, fh):
dirents = ['.', '..']
dirents.extend(self._list_dir(path))
for r in dirents:
yield r
def readlink(self, path):
return os.readlink(self._full_path(path))
def mknod(self, path, mode, dev):
return os.mknod(self._full_path(path), mode, dev)
def rmdir(self, path):
list_dir = self._list_dir(path)
if len(list_dir) > 0:
raise FuseOSError(errno.ENOANO)
self._remove_handle(path)
def mkdir(self, path, mode):
handle = self._get_handle_path(path)
if handle is not None:
raise FuseOSError(errno.ENOANO)
self._create_handle(path, True, dir_stv=self._create_new_dir_st(mode))
return
def statfs(self, path):
handle = self._get_handle_path(path)
if self._is_dir_handle(handle):
stv = os.statvfs(self.root)
else:
full_path = self._full_path(path)
stv = os.statvfs(full_path)
return dict((key, getattr(stv, key)) for key in ('f_bavail', 'f_bfree',
'f_blocks', 'f_bsize', 'f_favail', 'f_ffree', 'f_files',
'f_flag',
'f_frsize', 'f_namemax'))
def unlink(self, path):
res = os.unlink(self._full_path(path))
self._remove_handle(path)
return res
def symlink(self, name, target):
handle = self._get_handle_path(name)
if handle is not None:
raise FuseOSError(errno.ENOANO)
path = os.path.abspath(os.path.join(self.mount_point, "." + os.path.split(name)[0], target))
if path.startswith(self.mount_point):
fuse_path = path[len(self.mount_point):]
res = os.symlink(hash_path(fuse_path), self._full_path(name))
else:
res = os.symlink(path, self._full_path(name))
self._create_handle(name, False, link_path=target)
return res
def rename(self, old, new):
handle = self._get_handle_path(old)
if handle is None:
raise FuseOSError(errno.ENOANO)
res = os.rename(self._full_path(old), self._full_path(new))
self._rename_handle(old, new)
return res
def link(self, target, name):
return os.link(self._full_path(target), self._full_path(name))
def utimens(self, path, times=None):
handle = self._get_handle_path(path)
if self._is_dir_handle(handle):
stv = self._get_dir_stv(handle)
atime, mtime = times if times else (time(), time())
stv['st_atime'] = atime
stv['st_mtime'] = mtime
self._update_dir_stv(handle, stv)
return
elif handle[5] is not None:
return
return os.utime(self._full_path(path), times)
# File methods
# ============
def open(self, path, flags):
full_path = self._full_path(path)
return os.open(full_path, flags)
def create(self, path, mode, fi=None):
handle = self._get_handle_path(path)
if handle is not None:
raise FuseOSError(errno.ENOANO)
res = os.open(self._full_path(path), os.O_WRONLY | os.O_CREAT, mode)
self._create_handle(path, False)
return res
def read(self, path, length, offset, fh):
os.lseek(fh, offset, os.SEEK_SET)
return os.read(fh, length)
def write(self, path, buf, offset, fh):
os.lseek(fh, offset, os.SEEK_SET)
return os.write(fh, buf)
def truncate(self, path, length, fh=None):
full_path = self._full_path(path)
with open(full_path, 'r+') as f:
f.truncate(length)
def flush(self, path, fh):
return os.fsync(fh)
def release(self, path, fh):
return os.close(fh)
def fsync(self, path, fdatasync, fh):
return self.flush(path, fh)
def main(mountpoint, root):
FUSE(FlatFS(root, mountpoint), mountpoint, nothreads=True, foreground=True, debug=False)
if __name__ == '__main__':
main(sys.argv[2], sys.argv[1])