用Python编写一个简单的FUSE文件系统的教程

#!/usr/bin/env python from __future__ import with_statement import osimport sysimport errno from fuse import FUSE, FuseOSError, Operations class Passthrough(Operations):  def __init__(self, root):    self.root = root   # Helpers  # =======   def _full_path(self, partial):    if partial.startswith("/"):      partial = partial[1:]    path = os.path.join(self.root, partial)    return path   # Filesystem methods  # ==================   def access(self, path, mode):    full_path = self._full_path(path)    if not os.access(full_path, mode):      raise FuseOSError(errno.EACCES)   def chmod(self, path, mode):    full_path = self._full_path(path)    return os.chmod(full_path, mode)   def chown(self, path, uid, gid):    full_path = self._full_path(path)    return os.chown(full_path, uid, gid)   def getattr(self, path, fh=None):    full_path = self._full_path(path)    st = os.lstat(full_path)    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'))   def readdir(self, path, fh):    full_path = self._full_path(path)     dirents = ['.', '..']    if os.path.isdir(full_path):      dirents.extend(os.listdir(full_path))    for r in dirents:      yield r   def readlink(self, path):    pathname = os.readlink(self._full_path(path))    if pathname.startswith("/"):      # Path name is absolute, sanitize it.      return os.path.relpath(pathname, self.root)    else:      return pathname   def mknod(self, path, mode, dev):    return os.mknod(self._full_path(path), mode, dev)   def rmdir(self, path):    full_path = self._full_path(path)    return os.rmdir(full_path)   def mkdir(self, path, mode):    return os.mkdir(self._full_path(path), mode)   def statfs(self, path):    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):    return os.unlink(self._full_path(path))   def symlink(self, target, name):    return os.symlink(self._full_path(target), self._full_path(name))   def rename(self, old, new):    return os.rename(self._full_path(old), self._full_path(new))   def link(self, target, name):    return os.link(self._full_path(target), self._full_path(name))   def utimens(self, path, times=None):    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):    full_path = self._full_path(path)    return os.open(full_path, os.O_WRONLY | os.O_CREAT, mode)   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(Passthrough(root), mountpoint, foreground=True) if __name__ == '__main__':  main(sys.argv[2], sys.argv[1])