zeroedfs.py

import errno
import os
import sys
import fuse

fuse.fuse_python_api = (0, 2)


class Stat(fuse.Stat):
    def __init__(self, sb):
        for attr in ('st_atime', 'st_ctime', 'st_gid', 'st_mode', 'st_mtime',
                     'st_nlink', 'st_size', 'st_uid', 'st_dev', 'st_ino'):
            setattr(self, attr, getattr(sb, attr))


class ZeroedFS(fuse.Fuse):
    def __init__(self, *args, **kw):
        fuse.Fuse.__init__(self, *args, **kw)
        self.root = '/usr'

    def process_options(self, opts, args):
        print args

    def _fullpath(self, path):
        return os.path.join(self.root,
                            path[1:] if path.startswith("/") else path)

    def access(self, path, mode):
        if not os.access(self._fullpath(path), mode):
            return -errno.EACCES
        return 0

    def chmod(self, path, mode):
        return -errno.EACCES

    def chown(self, path, uid, gid):
        return -errno.EACCES

    def getattr(self, path, fh=None):
        sb = os.lstat(self._fullpath(path))
        return Stat(sb)

    def readdir(self, path, fh):
        fp = self._fullpath(path)
        if not os.path.isdir(fp):
            return

        yield fuse.Direntry('.')
        yield fuse.Direntry('..')
        for entry in os.listdir(fp):
            yield fuse.Direntry(entry)

    def readlink(self, path):
        return os.readlink(self._fullpath(path))

    def mknod(self, path, mode, dev):
        return -errno.EACCES

    def rmdir(self, path):
        return -errno.EACCES

    def mkdir(self, path):
        return -errno.EACCES

    # ~ def statfs(self, path):
        # ~ # TODO: ?
        # ~ pass

    def unlink(self, path):
        return -errno.EACCES

    def symlink(self, name, target):
        return -errno.EACCES

    def rename(self, old, new):
        return -errno.EACCES

    def link(self, target, name):
        return -errno.EACCES

    def utimens(self, path, times=None):
        return os.utime(self._fullpath(path), times)

    def open(self, path, flags):
        pass

    def create(self, path, mode, fi=None):
        return -errno.EACCES

    def read(self, path, length, offset):
        sb = os.lstat(self._fullpath(path))
        data_left = max(0, sb.st_size - offset)
        return bytes(bytearray(min(length, data_left)))

    def write(self, path, buf, offset):
        return -errno.EACCES

    def truncate(self, path, length, fh=None):
        return -errno.EACCES

    def release(self, path, fh):
        pass

    def fsync(self, path, fdatasync, fh):
        return


def main():
    usage = """
    ZeroedFS: Now without semi-colons!
    """ + fuse.Fuse.fusage

    server = ZeroedFS(version="%prog " + fuse.__version__,
                      usage=usage, dash_s_do='setsingle')
    server.parse(errex=1)
    server.main()


if __name__ == '__main__':
    main()