misc.py 文件源码

def ensure_dirs_gw(path, _parent_mode=False):
    """Ensure that path is a directory by creating it and parents if
    necessary.  Also ensure that it is group-writeable and
    -executable, and setgid. All created parent directories get their
    mode bits set comparably.

    This is a fairly specialized function used in support of the NRAO
    Lustre staging feature.

    Implementation copied from os.makedirs() with some tweaks.

    """
    import os.path
    import stat

    head, tail = os.path.split(path)  # /a/b/c => /a/b, c
    if not len(tail):  # if we got something like "a/b/" => ("a/b", "")
        head, tail = os.path.split(head)
    if len(head) and head != '/':
        ensure_dirs_gw(head, _parent_mode=True)

    try_chmod = not _parent_mode  # deepest directory must be g+wxs

    try:
        # Note: the `mode` passed to mkdir is altered by the umask, which may
        # remove the group-write bit we want, so we can't rely on it to set
        # permissions correctly.
        os.mkdir(path)
        try_chmod = True  # we created it, so definitely chmod
    except OSError as e:
        if e.errno == 17:
            pass  # already exists; no problem, and maybe no chmod
        elif e.errno == 13:  # EACCES
            raise Exception('unable to create directory \"%s\"; you probably '
                            'need to make its parent group-writeable with:\n\n'
                            'chmod g+wx \'%s\'' % (path, os.path.dirname(path)))
        else:
            raise

    if try_chmod:
        st = os.stat(path)
        mode = stat.S_IMODE(st.st_mode)
        new_mode = mode | (stat.S_IWUSR | stat.S_IWGRP | stat.S_IXUSR | stat.S_IXGRP | stat.S_ISGID)

        if new_mode != mode:  # avoid failure if perms are OK but we don't own the dir
            try:
                os.chmod(path, new_mode)
            except OSError as e:
                if e.errno == 1:  # EPERM
                    raise Exception('unable to make \"%s\" group-writeable; '
                                    'please do so yourself with:\n\nchmod g+wx \'%s\''
                                    % (path, path))
                raise