import ceph quincy 17.2.4

[ceph.git] / ceph / src / tools / cephfs / shell / cephfs-shell

#!/usr/bin/python3
# coding = utf-8

import argparse
import os
import os.path
import sys
import cephfs as libcephfs
import shutil
import traceback
import colorama
import fnmatch
import math
import re
import shlex
import stat
import errno

from cmd2 import Cmd
from cmd2 import __version__ as cmd2_version
from distutils.version import LooseVersion

if sys.version_info.major < 3:
    raise RuntimeError("cephfs-shell is only compatible with python3")

try:
    from cmd2 import with_argparser
except ImportError:
    def with_argparser(argparser):
        import functools

        def argparser_decorator(func):
            @functools.wraps(func)
            def wrapper(thiz, cmdline):
                if isinstance(cmdline, list):
                    arglist = cmdline
                else:
                    # do not split if it's already a list
                    arglist = shlex.split(cmdline, posix=False)
                    # in case user quotes the command args
                    arglist = [arg.strip('\'""') for arg in arglist]
                try:
                    args = argparser.parse_args(arglist)
                except SystemExit:
                    shell.exit_code = 1
                    # argparse exits at seeing bad arguments
                    return
                else:
                    return func(thiz, args)
            argparser.prog = func.__name__[3:]
            if argparser.description is None and func.__doc__:
                argparser.description = func.__doc__

            return wrapper

        return argparser_decorator


cephfs = None   # holds CephFS Python bindings
shell = None    # holds instance of class CephFSShell
exit_codes = {'Misc': 1,
              'KeyboardInterrupt': 2,
              errno.EPERM: 3,
              errno.EACCES: 4,
              errno.ENOENT: 5,
              errno.EIO: 6,
              errno.ENOSPC: 7,
              errno.EEXIST: 8,
              errno.ENODATA: 9,
              errno.EINVAL: 10,
              errno.EOPNOTSUPP: 11,
              errno.ERANGE: 12,
              errno.EWOULDBLOCK: 13,
              errno.ENOTEMPTY: 14,
              errno.ENOTDIR: 15,
              errno.EDQUOT: 16,
              errno.EPIPE: 17,
              errno.ESHUTDOWN: 18,
              errno.ECONNABORTED: 19,
              errno.ECONNREFUSED: 20,
              errno.ECONNRESET: 21,
              errno.EINTR: 22}


#########################################################################
#
# Following are methods are generically useful through class CephFSShell
#
#######################################################################


def poutput(s, end='\n'):
    shell.poutput(s, end=end)


def perror(msg, **kwargs):
    shell.perror(msg, **kwargs)


def set_exit_code_msg(errcode='Misc', msg=''):
    """
    Set exit code and print error message
    """
    if isinstance(msg, libcephfs.Error):
        shell.exit_code = exit_codes[msg.get_error_code()]
    else:
        shell.exit_code = exit_codes[errcode]
    if msg:
        perror(msg)


def mode_notation(mode):
    """
    """
    permission_bits = {'0': '---',
                       '1': '--x',
                       '2': '-w-',
                       '3': '-wx',
                       '4': 'r--',
                       '5': 'r-x',
                       '6': 'rw-',
                       '7': 'rwx'}
    mode = str(oct(mode))
    notation = '-'
    if mode[2] == '4':
        notation = 'd'
    elif mode[2:4] == '12':
        notation = 'l'
    for i in mode[-3:]:
        notation += permission_bits[i]
    return notation


def get_chunks(file_size):
    chunk_start = 0
    chunk_size = 0x20000  # 131072 bytes, default max ssl buffer size
    while chunk_start + chunk_size < file_size:
        yield chunk_start, chunk_size
        chunk_start += chunk_size
    final_chunk_size = file_size - chunk_start
    yield chunk_start, final_chunk_size


def to_bytes(param):
    # don't convert as follows as it can lead unusable results like coverting
    # [1, 2, 3, 4] to '[1, 2, 3, 4]' -
    # str(param).encode('utf-8')
    if isinstance(param, bytes):
        return param
    elif isinstance(param, str):
        return bytes(param, encoding='utf-8')
    elif isinstance(param, list):
        return [i.encode('utf-8') if isinstance(i, str) else to_bytes(i) for
                i in param]
    elif isinstance(param, int) or isinstance(param, float):
        return str(param).encode('utf-8')
    elif param is None:
        return None


def ls(path, opts=''):
    # opts tries to be like /bin/ls opts
    almost_all = 'A' in opts
    try:
        with cephfs.opendir(path) as d:
            while True:
                dent = cephfs.readdir(d)
                if dent is None:
                    return
                elif almost_all and dent.d_name in (b'.', b'..'):
                    continue
                yield dent
    except libcephfs.ObjectNotFound as e:
        set_exit_code_msg(msg=e)


def glob(path, pattern):
    paths = []
    parent_dir = os.path.dirname(path)
    if parent_dir == b'':
        parent_dir = b'/'
    if path == b'/' or is_dir_exists(os.path.basename(path), parent_dir):
        for i in ls(path, opts='A'):
            if fnmatch.fnmatch(i.d_name, pattern):
                paths.append(os.path.join(path, i.d_name))
    return paths


def locate_file(name, case_sensitive=True):
    dir_list = sorted(set(dirwalk(cephfs.getcwd())))
    if not case_sensitive:
        return [dname for dname in dir_list if name.lower() in dname.lower()]
    else:
        return [dname for dname in dir_list if name in dname]


def get_all_possible_paths(pattern):
    complete_pattern = pattern[:]
    paths = []
    is_rel_path = not os.path.isabs(pattern)
    if is_rel_path:
        dir_ = cephfs.getcwd()
    else:
        dir_ = b'/'
        pattern = pattern[1:]
    patterns = pattern.split(b'/')
    paths.extend(glob(dir_, patterns[0]))
    patterns.pop(0)
    for pattern in patterns:
        for path in paths:
            paths.extend(glob(path, pattern))
    if is_rel_path:
        complete_pattern = os.path.join(cephfs.getcwd(), complete_pattern)
    return [path for path in paths if fnmatch.fnmatch(path, complete_pattern)]


suffixes = ['B', 'K', 'M', 'G', 'T', 'P']


def humansize(nbytes):
    i = 0
    while nbytes >= 1024 and i < len(suffixes) - 1:
        nbytes /= 1024.
        i += 1
    nbytes = math.ceil(nbytes)
    f = ('%d' % nbytes).rstrip('.')
    return '%s%s' % (f, suffixes[i])


def style_listing(path, is_dir, is_symlink, ls_long=False):
    if not (is_dir or is_symlink):
        return path
    pretty = colorama.Style.BRIGHT
    if is_symlink:
        pretty += colorama.Fore.CYAN + path
        if ls_long:
            # Add target path
            pretty += ' -> ' + cephfs.readlink(path, size=255).decode('utf-8')
    elif is_dir:
        pretty += colorama.Fore.BLUE + path + '/'
    pretty += colorama.Style.RESET_ALL
    return pretty


def print_long(path, is_dir, is_symlink, human_readable):
    info = cephfs.stat(path, follow_symlink=(not is_symlink))
    pretty = style_listing(os.path.basename(path.decode('utf-8')), is_dir, is_symlink, True)
    if human_readable:
        sizefmt = '\t {:10s}'.format(humansize(info.st_size))
    else:
        sizefmt = '{:12d}'.format(info.st_size)
    poutput(f'{mode_notation(info.st_mode)} {sizefmt} {info.st_uid} {info.st_gid} {info.st_mtime}'
            f' {pretty}')


def word_len(word):
    """
    Returns the word length, minus any color codes.
    """
    if word[0] == '\x1b':
        return len(word) - 9
    return len(word)


def is_dir_exists(path, dir_=b''):
    path_to_stat = os.path.join(dir_, path)
    try:
        return ((cephfs.stat(path_to_stat).st_mode & 0o0040000) != 0)
    except libcephfs.Error:
        return False


def is_file_exists(path, dir_=b''):
    try:
        # if its not a directory, then its a file
        return ((cephfs.stat(os.path.join(dir_, path)).st_mode & 0o0040000) == 0)
    except libcephfs.Error:
        return False


def print_list(words, termwidth=79):
    if not words:
        return
    words = [word.decode('utf-8') if isinstance(word, bytes) else word for word in words]
    width = max([word_len(word) for word in words]) + 2
    nwords = len(words)
    ncols = max(1, (termwidth + 1) // (width + 1))
    nrows = (nwords + ncols - 1) // ncols
    for row in range(nrows):
        for i in range(row, nwords, nrows):
            word = words[i]
            print_width = width
            if word[0] == '\x1b':
                print_width = print_width + 10

            poutput('%-*s' % (print_width, words[i]),
                    end='\n' if i + nrows >= nwords else '')


def copy_from_local(local_path, remote_path):
    stdin = -1
    file_ = None
    fd = None
    convert_to_bytes = False
    if local_path == b'-':
        file_ = sys.stdin
        convert_to_bytes = True
    else:
        try:
            file_ = open(local_path, 'rb')
        except PermissionError as e:
            set_exit_code_msg(e.errno, 'error: no permission to read local file {}'.format(
                local_path.decode('utf-8')))
            return
        stdin = 1
    try:
        fd = cephfs.open(remote_path, 'w', 0o666)
    except libcephfs.Error as e:
        set_exit_code_msg(msg=e)
        return
    progress = 0
    while True:
        data = file_.read(65536)
        if not data or len(data) == 0:
            break
        if convert_to_bytes:
            data = to_bytes(data)
        wrote = cephfs.write(fd, data, progress)
        if wrote < 0:
            break
        progress += wrote
    cephfs.close(fd)
    if stdin > 0:
        file_.close()
    poutput('')


def copy_to_local(remote_path, local_path):
    fd = None
    if local_path != b'-':
        local_dir = os.path.dirname(local_path)
        dir_list = remote_path.rsplit(b'/', 1)
        if not os.path.exists(local_dir):
            os.makedirs(local_dir)
        if len(dir_list) > 2 and dir_list[1] == b'':
            return
        fd = open(local_path, 'wb+')
    file_ = cephfs.open(remote_path, 'r')
    file_size = cephfs.stat(remote_path).st_size
    if file_size <= 0:
        return
    progress = 0
    for chunk_start, chunk_size in get_chunks(file_size):
        file_chunk = cephfs.read(file_, chunk_start, chunk_size)
        progress += len(file_chunk)
        if fd:
            fd.write(file_chunk)
        else:
            poutput(file_chunk.decode('utf-8'))
    cephfs.close(file_)
    if fd:
        fd.close()


def dirwalk(path):
    """
    walk a directory tree, using a generator
    """
    path = os.path.normpath(path)
    for item in ls(path, opts='A'):
        fullpath = os.path.join(path, item.d_name)
        src_path = fullpath.rsplit(b'/', 1)[0]

        yield os.path.normpath(fullpath)
        if is_dir_exists(item.d_name, src_path):
            for x in dirwalk(fullpath):
                yield x


##################################################################
#
# Following methods are implementation for CephFS Shell commands
#
#################################################################

class CephFSShell(Cmd):

    def __init__(self):
        super().__init__()
        self.working_dir = cephfs.getcwd().decode('utf-8')
        self.set_prompt()
        self.interactive = False
        self.umask = '2'

    def default(self, line):
        perror('Unrecognized command')

    def set_prompt(self):
        self.prompt = ('\033[01;33mCephFS:~' + colorama.Fore.LIGHTCYAN_EX
                       + self.working_dir + colorama.Style.RESET_ALL
                       + '\033[01;33m>>>\033[00m ')

    def create_argparser(self, command):
        try:
            argparse_args = getattr(self, 'argparse_' + command)
        except AttributeError:
            set_exit_code_msg()
            return None
        doc_lines = getattr(
            self, 'do_' + command).__doc__.expandtabs().splitlines()
        if '' in doc_lines:
            blank_idx = doc_lines.index('')
            usage = doc_lines[:blank_idx]
            description = doc_lines[blank_idx + 1:]
        else:
            usage = doc_lines
            description = []
        parser = argparse.ArgumentParser(
            prog=command,
            usage='\n'.join(usage),
            description='\n'.join(description),
            formatter_class=argparse.ArgumentDefaultsHelpFormatter
        )
        for args, kwargs in argparse_args:
            parser.add_argument(*args, **kwargs)
        return parser

    def complete_filenames(self, text, line, begidx, endidx):
        if not text:
            completions = [x.d_name.decode('utf-8') + '/' * int(x.is_dir())
                           for x in ls(b".", opts='A')]
        else:
            if text.count('/') > 0:
                completions = [text.rsplit('/', 1)[0] + '/'
                               + x.d_name.decode('utf-8') + '/'
                               * int(x.is_dir()) for x in ls('/'
                               + text.rsplit('/', 1)[0], opts='A')
                               if x.d_name.decode('utf-8').startswith(
                                   text.rsplit('/', 1)[1])]
            else:
                completions = [x.d_name.decode('utf-8') + '/'
                               * int(x.is_dir()) for x in ls(b".", opts='A')
                               if x.d_name.decode('utf-8').startswith(text)]
            if len(completions) == 1 and completions[0][-1] == '/':
                dir_, file_ = completions[0].rsplit('/', 1)
                completions.extend([dir_ + '/' + x.d_name.decode('utf-8')
                                    + '/' * int(x.is_dir()) for x in
                                    ls('/' + dir_, opts='A')
                                    if x.d_name.decode('utf-8').startswith(file_)])
            return self.delimiter_complete(text, line, begidx, endidx, completions, '/')
        return completions

    def onecmd(self, line, **kwargs):
        """
        Global error catcher
        """
        try:
            res = Cmd.onecmd(self, line, **kwargs)
            if self.interactive:
                self.set_prompt()
            return res
        except ConnectionError as e:
            set_exit_code_msg(e.errno, f'***\n{e}')
        except KeyboardInterrupt:
            set_exit_code_msg('KeyboardInterrupt', 'Command aborted')
        except (libcephfs.Error, Exception) as e:
            if shell.debug:
                traceback.print_exc(file=sys.stdout)
            set_exit_code_msg(msg=e)

    class path_to_bytes(argparse.Action):
        def __call__(self, parser, namespace, values, option_string=None):
            values = to_bytes(values)
            setattr(namespace, self.dest, values)

    # TODO: move the necessary contents from here to `class path_to_bytes`.
    class get_list_of_bytes_path(argparse.Action):
        def __call__(self, parser, namespace, values, option_string=None):
            values = to_bytes(values)

            if values == b'.':
                values = cephfs.getcwd()
            else:
                for i in values:
                    if i == b'.':
                        values[values.index(i)] = cephfs.getcwd()

            setattr(namespace, self.dest, values)

    def complete_mkdir(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    class ModeAction(argparse.Action):
        def __init__(self, option_strings, dest, nargs=None, **kwargs):
            if nargs is not None and nargs != '?':
                raise ValueError("more than one modes not allowed")
            super().__init__(option_strings, dest, **kwargs)

        def __call__(self, parser, namespace, values, option_string=None):
            o_mode = 0
            res = None
            try:
                o_mode = int(values, base=8)
            except ValueError:
                res = re.match('((u?g?o?)|(a?))(=)(r?w?x?)', values)
                if res is None:
                    parser.error("invalid mode: %s\n"
                                 "mode must be a numeric octal literal\n"
                                 "or   ((u?g?o?)|(a?))(=)(r?w?x?)" %
                                 values)
                else:
                    # we are supporting only assignment of mode and not + or -
                    # as is generally available with the chmod command
                    # eg.
                    # >>> res = re.match('((u?g?o?)|(a?))(=)(r?w?x?)', 'go=')
                    # >>> res.groups()
                    # ('go', 'go', None, '=', '')
                    val = res.groups()

                    if val[3] != '=':
                        parser.error("need assignment operator between user "
                                     "and mode specifiers")
                    if val[4] == '':
                        parser.error("invalid mode: %s\n"
                                     "mode must be combination of: r | w | x" %
                                     values)
                    users = ''
                    if val[2] is None:
                        users = val[1]
                    else:
                        users = val[2]

                    t_mode = 0
                    if users == 'a':
                        users = 'ugo'

                    if 'r' in val[4]:
                        t_mode |= 4
                    if 'w' in val[4]:
                        t_mode |= 2
                    if 'x' in val[4]:
                        t_mode |= 1

                    if 'u' in users:
                        o_mode |= (t_mode << 6)
                    if 'g' in users:
                        o_mode |= (t_mode << 3)
                    if 'o' in users:
                        o_mode |= t_mode

            if o_mode < 0:
                parser.error("invalid mode: %s\n"
                             "mode cannot be negative" % values)
            if o_mode > 0o777:
                parser.error("invalid mode: %s\n"
                             "mode cannot be greater than octal 0777" % values)

            setattr(namespace, self.dest, str(oct(o_mode)))

    mkdir_parser = argparse.ArgumentParser(
        description='Create the directory(ies), if they do not already exist.')
    mkdir_parser.add_argument('dirs', type=str,
                              action=path_to_bytes,
                              metavar='DIR_NAME',
                              help='Name of new_directory.',
                              nargs='+')
    mkdir_parser.add_argument('-m', '--mode', type=str,
                              action=ModeAction,
                              help='Sets the access mode for the new directory.')
    mkdir_parser.add_argument('-p', '--parent', action='store_true',
                              help='Create parent directories as necessary. '
                                   'When this option is specified, no error is'
                                   'reported if a directory already exists.')

    @with_argparser(mkdir_parser)
    def do_mkdir(self, args):
        """
        Create directory.
        """
        for path in args.dirs:
            if args.mode:
                permission = int(args.mode, 8)
            else:
                permission = 0o777
            if args.parent:
                cephfs.mkdirs(path, permission)
            else:
                try:
                    cephfs.mkdir(path, permission)
                except libcephfs.Error as e:
                    set_exit_code_msg(e)

    def complete_put(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        index_dict = {1: self.path_complete}
        return self.index_based_complete(text, line, begidx, endidx, index_dict)

    put_parser = argparse.ArgumentParser(
        description='Copy a file/directory to Ceph File System from Local File System.')
    put_parser.add_argument('local_path', type=str, action=path_to_bytes,
                            help='Path of the file in the local system')
    put_parser.add_argument('remote_path', type=str, action=path_to_bytes,
                            help='Path of the file in the remote system')
    put_parser.add_argument('-f', '--force', action='store_true',
                            help='Overwrites the destination if it already exists.')

    @with_argparser(put_parser)
    def do_put(self, args):
        """
        Copy a local file/directory to CephFS.
        """
        if args.local_path != b'-' and not os.path.isfile(args.local_path) \
                and not os.path.isdir(args.local_path):
            set_exit_code_msg(errno.ENOENT,
                              msg=f"error: "
                                  f"{args.local_path.decode('utf-8')}: "
                                  f"No such file or directory")
            return

        if (is_file_exists(args.remote_path) or is_dir_exists(
                args.remote_path)) and not args.force:
            set_exit_code_msg(msg=f"error: file/directory "
                                  f"{args.remote_path.decode('utf-8')} "
                                  f"exists, use --force to overwrite")
            return

        root_src_dir = args.local_path
        root_dst_dir = args.remote_path
        if args.local_path == b'.' or args.local_path == b'./':
            root_src_dir = os.getcwdb()
        elif len(args.local_path.rsplit(b'/', 1)) < 2:
            root_src_dir = os.path.join(os.getcwdb(), args.local_path)
        else:
            p = args.local_path.split(b'/')
            if p[0] == b'.':
                root_src_dir = os.getcwdb()
                p.pop(0)
                while len(p) > 0:
                    root_src_dir += b'/' + p.pop(0)

        if root_dst_dir == b'.':
            if args.local_path != b'-':
                root_dst_dir = root_src_dir.rsplit(b'/', 1)[1]
                if root_dst_dir == b'':
                    root_dst_dir = root_src_dir.rsplit(b'/', 1)[0]
                    a = root_dst_dir.rsplit(b'/', 1)
                    if len(a) > 1:
                        root_dst_dir = a[1]
                    else:
                        root_dst_dir = a[0]
            else:
                set_exit_code_msg(errno.EINVAL, 'error: no filename specified '
                                  'for destination')
                return

        if root_dst_dir[-1] != b'/':
            root_dst_dir += b'/'

        if args.local_path == b'-' or os.path.isfile(root_src_dir):
            if args.local_path == b'-':
                root_src_dir = b'-'
            copy_from_local(root_src_dir, root_dst_dir)
        else:
            for src_dir, dirs, files in os.walk(root_src_dir):
                if isinstance(src_dir, str):
                    src_dir = to_bytes(src_dir)
                dst_dir = src_dir.replace(root_src_dir, root_dst_dir, 1)
                dst_dir = re.sub(rb'\/+', b'/', cephfs.getcwd()
                                 + dst_dir)
                if args.force and dst_dir != b'/' and not is_dir_exists(
                        dst_dir[:-1]) and not locate_file(dst_dir):
                    try:
                        cephfs.mkdirs(dst_dir, 0o777)
                    except libcephfs.Error:
                        pass
                if (not args.force) and dst_dir != b'/' and not is_dir_exists(
                        dst_dir) and not os.path.isfile(root_src_dir):
                    try:
                        cephfs.mkdirs(dst_dir, 0o777)
                    except libcephfs.Error:
                        # TODO: perhaps, set retval to 1?
                        pass

                for dir_ in dirs:
                    dir_name = os.path.join(dst_dir, dir_)
                    if not is_dir_exists(dir_name):
                        try:
                            cephfs.mkdirs(dir_name, 0o777)
                        except libcephfs.Error:
                            # TODO: perhaps, set retval to 1?
                            pass

                for file_ in files:
                    src_file = os.path.join(src_dir, file_)
                    dst_file = re.sub(rb'\/+', b'/', b'/' + dst_dir + b'/' + file_)
                    if (not args.force) and is_file_exists(dst_file):
                        return
                    copy_from_local(src_file, os.path.join(cephfs.getcwd(),
                                    dst_file))

    def complete_get(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    get_parser = argparse.ArgumentParser(
        description='Copy a file from Ceph File System to Local Directory.')
    get_parser.add_argument('remote_path', type=str, action=path_to_bytes,
                            help='Path of the file in the remote system')
    get_parser.add_argument('local_path', type=str, action=path_to_bytes,
                            help='Path of the file in the local system')
    get_parser.add_argument('-f', '--force', action='store_true',
                            help='Overwrites the destination if it already exists.')

    @with_argparser(get_parser)
    def do_get(self, args):
        """
        Copy a file/directory from CephFS to given path.
        """
        if not is_file_exists(args.remote_path) and not \
                is_dir_exists(args.remote_path):
            set_exit_code_msg(errno.ENOENT, "error: no file/directory"
                                            " found at specified remote "
                                            "path")
            return
        if (os.path.isfile(args.local_path) or os.path.isdir(
                args.local_path)) and not args.force:
            set_exit_code_msg(msg=f"error: file/directory "
                                  f"{args.local_path.decode('utf-8')}"
                                  f" already exists, use --force to "
                                  f"overwrite")
            return
        root_src_dir = args.remote_path
        root_dst_dir = args.local_path
        fname = root_src_dir.rsplit(b'/', 1)
        if args.local_path == b'.':
            root_dst_dir = os.getcwdb()
        if args.remote_path == b'.':
            root_src_dir = cephfs.getcwd()
        if args.local_path == b'-':
            if args.remote_path == b'.' or args.remote_path == b'./':
                set_exit_code_msg(errno.EINVAL, 'error: no remote file name specified')
                return
            copy_to_local(root_src_dir, b'-')
        elif is_file_exists(args.remote_path):
            copy_to_local(root_src_dir, root_dst_dir)
        elif b'/' in root_src_dir and is_file_exists(fname[1], fname[0]):
            copy_to_local(root_src_dir, root_dst_dir)
        else:
            files = list(reversed(sorted(dirwalk(root_src_dir))))
            for file_ in files:
                dst_dirpath, dst_file = file_.rsplit(b'/', 1)
                if dst_dirpath in files:
                    files.remove(dst_dirpath)
                dst_path = os.path.join(root_dst_dir, dst_dirpath, dst_file)
                dst_path = os.path.normpath(dst_path)
                if is_dir_exists(file_):
                    try:
                        os.makedirs(dst_path)
                    except OSError:
                        pass
                else:
                    copy_to_local(file_, dst_path)

        return 0

    def complete_ls(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    ls_parser = argparse.ArgumentParser(
        description='Copy a file from Ceph File System from Local Directory.')
    ls_parser.add_argument('-l', '--long', action='store_true',
                           help='Detailed list of items in the directory.')
    ls_parser.add_argument('-r', '--reverse', action='store_true',
                           help='Reverse order of listing items in the directory.')
    ls_parser.add_argument('-H', action='store_true', help='Human Readable')
    ls_parser.add_argument('-a', '--all', action='store_true',
                           help='Do not Ignore entries starting with .')
    ls_parser.add_argument('-S', action='store_true', help='Sort by file_size')
    ls_parser.add_argument('paths', help='Name of Directories',
                           action=path_to_bytes, nargs='*', default=['.'])

    @with_argparser(ls_parser)
    def do_ls(self, args):
        """
        List all the files and directories in the current working directory
        """
        paths = args.paths
        for path in paths:
            values = []
            items = []
            try:
                if path.count(b'*') > 0:
                    all_items = get_all_possible_paths(path)
                    if len(all_items) == 0:
                        continue
                    path = all_items[0].rsplit(b'/', 1)[0]
                    if path == b'':
                        path = b'/'
                    dirs = []
                    for i in all_items:
                        for item in ls(path):
                            d_name = item.d_name
                            if os.path.basename(i) == d_name:
                                if item.is_dir():
                                    dirs.append(os.path.join(path, d_name))
                                else:
                                    items.append(item)
                    if dirs:
                        paths.extend(dirs)
                    else:
                        poutput(path.decode('utf-8'), end=':\n')
                    items = sorted(items, key=lambda item: item.d_name)
                else:
                    if path != b'' and path != cephfs.getcwd() and len(paths) > 1:
                        poutput(path.decode('utf-8'), end=':\n')
                    items = sorted(ls(path), key=lambda item: item.d_name)
                if not args.all:
                    items = [i for i in items if not i.d_name.startswith(b'.')]
                if args.S:
                    items = sorted(items, key=lambda item: cephfs.stat(
                        path + b'/' + item.d_name, follow_symlink=(
                            not item.is_symbol_file())).st_size)
                if args.reverse:
                    items = reversed(items)
                for item in items:
                    filepath = item.d_name
                    is_dir = item.is_dir()
                    is_sym_lnk = item.is_symbol_file()
                    try:
                        if args.long and args.H:
                            print_long(os.path.join(cephfs.getcwd(), path, filepath), is_dir,
                                       is_sym_lnk, True)
                        elif args.long:
                            print_long(os.path.join(cephfs.getcwd(), path, filepath), is_dir,
                                       is_sym_lnk, False)
                        elif is_sym_lnk or is_dir:
                            values.append(style_listing(filepath.decode('utf-8'), is_dir,
                                          is_sym_lnk))
                        else:
                            values.append(filepath)
                    except libcephfs.Error as e:
                        set_exit_code_msg(msg=e)
                if not args.long:
                    print_list(values, shutil.get_terminal_size().columns)
                    if path != paths[-1]:
                        poutput('')
            except libcephfs.Error as e:
                set_exit_code_msg(msg=e)

    def complete_rmdir(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    rmdir_parser = argparse.ArgumentParser(description='Remove Directory.')
    rmdir_parser.add_argument('paths', help='Directory Path.', nargs='+',
                              action=path_to_bytes)
    rmdir_parser.add_argument('-p', '--parent', action='store_true',
                              help='Remove parent directories as necessary. '
                                   'When this option is specified, no error '
                                    'is reported if a directory has any '
                                    'sub-directories, files')

    @with_argparser(rmdir_parser)
    def do_rmdir(self, args):
        self.do_rmdir_helper(args)

    def do_rmdir_helper(self, args):
        """
        Remove a specific Directory
        """
        is_pattern = False
        paths = args.paths
        for path in paths:
            if path.count(b'*') > 0:
                is_pattern = True
                all_items = get_all_possible_paths(path)
                if len(all_items) > 0:
                    path = all_items[0].rsplit(b'/', 1)[0]
                if path == b'':
                    path = b'/'
                dirs = []
                for i in all_items:
                    for item in ls(path):
                        d_name = item.d_name
                        if os.path.basename(i) == d_name:
                            if item.is_dir():
                                dirs.append(os.path.join(path, d_name))
                paths.extend(dirs)
                continue
            else:
                is_pattern = False

            if args.parent:
                path = os.path.join(cephfs.getcwd(), path.rsplit(b'/')[0])
                files = list(sorted(set(dirwalk(path)), reverse=True))
                if not files:
                    path = b'.'
                for filepath in files:
                    try:
                        cephfs.rmdir(os.path.normpath(filepath))
                    except libcephfs.Error as e:
                        perror(e)
                        path = b'.'
                        break
            else:
                path = os.path.normpath(os.path.join(cephfs.getcwd(), path))
            if not is_pattern and path != os.path.normpath(b''):
                try:
                    cephfs.rmdir(path)
                except libcephfs.Error as e:
                    set_exit_code_msg(msg=e)

    def complete_rm(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    rm_parser = argparse.ArgumentParser(description='Remove File.')
    rm_parser.add_argument('paths', help='File Path.', nargs='+',
                           action=path_to_bytes)

    @with_argparser(rm_parser)
    def do_rm(self, args):
        """
        Remove a specific file
        """
        file_paths = args.paths
        for path in file_paths:
            if path.count(b'*') > 0:
                file_paths.extend([i for i in get_all_possible_paths(
                    path) if is_file_exists(i)])
            else:
                try:
                    cephfs.unlink(path)
                except libcephfs.Error as e:
                    # NOTE: perhaps we need a better msg here
                    set_exit_code_msg(msg=e)

    def complete_mv(self, text, line, begidx, endidx):
        """
         auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    mv_parser = argparse.ArgumentParser(description='Move File.')
    mv_parser.add_argument('src_path', type=str, action=path_to_bytes,
                           help='Source File Path.')
    mv_parser.add_argument('dest_path', type=str, action=path_to_bytes,
                           help='Destination File Path.')

    @with_argparser(mv_parser)
    def do_mv(self, args):
        """
        Rename a file or Move a file from source path to the destination
        """
        cephfs.rename(args.src_path, args.dest_path)

    def complete_cd(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    cd_parser = argparse.ArgumentParser(description='Change working directory')
    cd_parser.add_argument('path', type=str, help='Name of the directory.',
                           action=path_to_bytes, nargs='?', default='/')

    @with_argparser(cd_parser)
    def do_cd(self, args):
        """
        Change working directory
        """
        cephfs.chdir(args.path)
        self.working_dir = cephfs.getcwd().decode('utf-8')
        self.set_prompt()

    def do_cwd(self, arglist):
        """
        Get current working directory.
        """
        poutput(cephfs.getcwd().decode('utf-8'))

    def complete_chmod(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    chmod_parser = argparse.ArgumentParser(description='Create Directory.')
    chmod_parser.add_argument('mode', type=str, action=ModeAction, help='Mode')
    chmod_parser.add_argument('paths', type=str, action=path_to_bytes,
                              help='Name of the file', nargs='+')

    @with_argparser(chmod_parser)
    def do_chmod(self, args):
        """
        Change permission of a file
        """
        for path in args.paths:
            mode = int(args.mode, base=8)
            try:
                cephfs.chmod(path, mode)
            except libcephfs.Error as e:
                set_exit_code_msg(msg=e)

    def complete_cat(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    cat_parser = argparse.ArgumentParser(description='')
    cat_parser.add_argument('paths', help='Name of Files', action=path_to_bytes,
                            nargs='+')

    @with_argparser(cat_parser)
    def do_cat(self, args):
        """
        Print contents of a file
        """
        for path in args.paths:
            if is_file_exists(path):
                copy_to_local(path, b'-')
            else:
                set_exit_code_msg(errno.ENOENT, '{}: no such file'.format(
                    path.decode('utf-8')))

    umask_parser = argparse.ArgumentParser(description='Set umask value.')
    umask_parser.add_argument('mode', help='Mode', type=str, action=ModeAction,
                              nargs='?', default='')

    @with_argparser(umask_parser)
    def do_umask(self, args):
        """
        Set Umask value.
        """
        if args.mode == '':
            poutput(self.umask.zfill(4))
        else:
            mode = int(args.mode, 8)
            self.umask = str(oct(cephfs.umask(mode))[2:])

    def complete_write(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    write_parser = argparse.ArgumentParser(description='Writes data into a file')
    write_parser.add_argument('path', type=str, action=path_to_bytes,
                              help='Name of File')

    @with_argparser(write_parser)
    def do_write(self, args):
        """
        Write data into a file.
        """

        copy_from_local(b'-', args.path)

    def complete_lcd(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        index_dict = {1: self.path_complete}
        return self.index_based_complete(text, line, begidx, endidx, index_dict)

    lcd_parser = argparse.ArgumentParser(description='')
    lcd_parser.add_argument('path', type=str, action=path_to_bytes, help='Path')

    @with_argparser(lcd_parser)
    def do_lcd(self, args):
        """
        Moves into the given local directory
        """
        try:
            os.chdir(os.path.expanduser(args.path))
        except OSError as e:
            set_exit_code_msg(e.errno, "Cannot change to "
                              f"{e.filename.decode('utf-8')}: {e.strerror}")

    def complete_lls(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        index_dict = {1: self.path_complete}
        return self.index_based_complete(text, line, begidx, endidx, index_dict)

    lls_parser = argparse.ArgumentParser(
        description='List files in local system.')
    lls_parser.add_argument('paths', help='Paths', action=path_to_bytes,
                            nargs='*')

    @with_argparser(lls_parser)
    def do_lls(self, args):
        """
        Lists all files and folders in the current local directory
        """
        if not args.paths:
            print_list(os.listdir(os.getcwdb()))
        else:
            for path in args.paths:
                try:
                    items = os.listdir(path)
                    poutput("{}:".format(path.decode('utf-8')))
                    print_list(items)
                except OSError as e:
                    set_exit_code_msg(e.errno, f"{e.filename.decode('utf-8')}: "
                                      f"{e.strerror}")
        # Arguments to the with_argpaser decorator function are sticky.
        # The items in args.path do not get overwritten in subsequent calls.
        # The arguments remain in args.paths after the function exits and we
        # neeed to clean it up to ensure the next call works as expected.
        args.paths.clear()

    def do_lpwd(self, arglist):
        """
        Prints the absolute path of the current local directory
        """
        poutput(os.getcwd())

    def complete_df(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    df_parser = argparse.ArgumentParser(description='Show information about\
                the amount of available disk space')
    df_parser.add_argument('file', help='Name of the file', nargs='*',
                           default=['.'], action=path_to_bytes)

    @with_argparser(df_parser)
    def do_df(self, arglist):
        """
        Display the amount of available disk space for file systems
        """
        header = True    # Set to true for printing header only once
        if b'.' == arglist.file[0]:
            arglist.file = ls(b'.')

        for file in arglist.file:
            if isinstance(file, libcephfs.DirEntry):
                file = file.d_name
            if file == b'.' or file == b'..':
                continue
            try:
                statfs = cephfs.statfs(file)
                stat = cephfs.stat(file)
                block_size = (statfs['f_blocks'] * statfs['f_bsize']) // 1024
                available = block_size - stat.st_size
                use = 0

                if block_size > 0:
                    use = (stat.st_size * 100) // block_size

                if header:
                    header = False
                    poutput('{:25s}\t{:5s}\t{:15s}{:10s}{}'.format(
                            "1K-blocks", "Used", "Available", "Use%",
                            "Stored on"))

                poutput('{:d}\t{:18d}\t{:8d}\t{:10s} {}'.format(block_size,
                        stat.st_size, available, str(int(use)) + '%',
                        file.decode('utf-8')))
            except libcephfs.OSError as e:
                set_exit_code_msg(e.get_error_code(), "could not statfs {}: {}".format(
                    file.decode('utf-8'), e.strerror))

    locate_parser = argparse.ArgumentParser(
        description='Find file within file system')
    locate_parser.add_argument('name', help='name', type=str,
                               action=path_to_bytes)
    locate_parser.add_argument('-c', '--count', action='store_true',
                               help='Count list of items located.')
    locate_parser.add_argument(
        '-i', '--ignorecase', action='store_true', help='Ignore case')

    @with_argparser(locate_parser)
    def do_locate(self, args):
        """
        Find a file within the File System
        """
        if args.name.count(b'*') == 1:
            if args.name[0] == b'*':
                args.name += b'/'
            elif args.name[-1] == '*':
                args.name = b'/' + args.name
        args.name = args.name.replace(b'*', b'')
        if args.ignorecase:
            locations = locate_file(args.name, False)
        else:
            locations = locate_file(args.name)
        if args.count:
            poutput(len(locations))
        else:
            poutput((b'\n'.join(locations)).decode('utf-8'))

    def complete_du(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    du_parser = argparse.ArgumentParser(
        description='Disk Usage of a Directory')
    du_parser.add_argument('paths', type=str, action=get_list_of_bytes_path,
                           help='Name of the directory.', nargs='*',
                           default=[b'.'])
    du_parser.add_argument('-r', action='store_true',
                           help='Recursive Disk usage of all directories.')

    @with_argparser(du_parser)
    def do_du(self, args):
        """
        Print disk usage of a given path(s).
        """
        def print_disk_usage(files):
            if isinstance(files, bytes):
                files = (files, )

            for f in files:
                try:
                    st = cephfs.lstat(f)

                    if stat.S_ISDIR(st.st_mode):
                        dusage = int(cephfs.getxattr(f,
                                     'ceph.dir.rbytes').decode('utf-8'))
                    else:
                        dusage = st.st_size

                    # print path in local context
                    f = os.path.normpath(f)
                    if f[0] is ord('/'):
                        f = b'.' + f
                    poutput('{:10s} {}'.format(humansize(dusage),
                            f.decode('utf-8')))
                except libcephfs.Error as e:
                    set_exit_code_msg(msg=e)
                    continue

        for path in args.paths:
            if args.r:
                print_disk_usage(sorted(set(dirwalk(path)).union({path})))
            else:
                print_disk_usage(path)

    quota_parser = argparse.ArgumentParser(
        description='Quota management for a Directory')
    quota_parser.add_argument('op', choices=['get', 'set'],
                              help='Quota operation type.')
    quota_parser.add_argument('path', type=str, action=path_to_bytes,
                              help='Name of the directory.')
    quota_parser.add_argument('--max_bytes', type=int, default=-1, nargs='?',
                              help='Max cumulative size of the data under '
                                   'this directory.')
    quota_parser.add_argument('--max_files', type=int, default=-1, nargs='?',
                              help='Total number of files under this '
                                   'directory tree.')

    @with_argparser(quota_parser)
    def do_quota(self, args):
        """
        Quota management.
        """
        if not is_dir_exists(args.path):
            set_exit_code_msg(errno.ENOENT, 'error: no such directory {}'.format(
                args.path.decode('utf-8')))
            return

        if args.op == 'set':
            if (args.max_bytes == -1) and (args.max_files == -1):
                set_exit_code_msg(errno.EINVAL, 'please specify either '
                                  '--max_bytes or --max_files or both')
                return

            if args.max_bytes >= 0:
                max_bytes = to_bytes(str(args.max_bytes))
                try:
                    cephfs.setxattr(args.path, 'ceph.quota.max_bytes',
                                    max_bytes, os.XATTR_CREATE)
                    poutput('max_bytes set to %d' % args.max_bytes)
                except libcephfs.Error as e:
                    cephfs.setxattr(args.path, 'ceph.quota.max_bytes',
                                    max_bytes, os.XATTR_REPLACE)
                    set_exit_code_msg(e.get_error_code(), 'max_bytes reset to '
                                      f'{args.max_bytes}')

            if args.max_files >= 0:
                max_files = to_bytes(str(args.max_files))
                try:
                    cephfs.setxattr(args.path, 'ceph.quota.max_files',
                                    max_files, os.XATTR_CREATE)
                    poutput('max_files set to %d' % args.max_files)
                except libcephfs.Error as e:
                    cephfs.setxattr(args.path, 'ceph.quota.max_files',
                                    max_files, os.XATTR_REPLACE)
                    set_exit_code_msg(e.get_error_code(), 'max_files reset to '
                                      f'{args.max_files}')
        elif args.op == 'get':
            max_bytes = '0'
            max_files = '0'
            try:
                max_bytes = cephfs.getxattr(args.path, 'ceph.quota.max_bytes')
                poutput('max_bytes: {}'.format(max_bytes.decode('utf-8')))
            except libcephfs.Error as e:
                set_exit_code_msg(e.get_error_code(), 'max_bytes is not set')

            try:
                max_files = cephfs.getxattr(args.path, 'ceph.quota.max_files')
                poutput('max_files: {}'.format(max_files.decode('utf-8')))
            except libcephfs.Error as e:
                set_exit_code_msg(e.get_error_code(), 'max_files is not set')

    snap_parser = argparse.ArgumentParser(description='Snapshot Management')
    snap_parser.add_argument('op', type=str,
                             help='Snapshot operation: create or delete')
    snap_parser.add_argument('name', type=str, action=path_to_bytes,
                             help='Name of snapshot')
    snap_parser.add_argument('dir', type=str, action=path_to_bytes,
                             help='Directory for which snapshot '
                                  'needs to be created or deleted')

    @with_argparser(snap_parser)
    def do_snap(self, args):
        """
        Snapshot management for the volume
        """
        # setting self.colors to None turns off colorizing and
        # perror emits plain text
        self.colors = None

        snapdir = '.snap'
        conf_snapdir = cephfs.conf_get('client_snapdir')
        if conf_snapdir is not None:
            snapdir = conf_snapdir
        snapdir = to_bytes(snapdir)
        if args.op == 'create':
            try:
                if is_dir_exists(args.dir):
                    cephfs.mkdir(os.path.join(args.dir, snapdir, args.name), 0o755)
                else:
                    set_exit_code_msg(errno.ENOENT, "'{}': no such directory".format(
                                      args.dir.decode('utf-8')))
            except libcephfs.Error as e:
                set_exit_code_msg(e.get_error_code(),
                                  "snapshot '{}' already exists".format(
                                  args.name.decode('utf-8')))
        elif args.op == 'delete':
            snap_dir = os.path.join(args.dir, snapdir, args.name)
            try:
                if is_dir_exists(snap_dir):
                    newargs = argparse.Namespace(paths=[snap_dir], parent=False)
                    self.do_rmdir_helper(newargs)
                else:
                    set_exit_code_msg(errno.ENOENT, "'{}': no such snapshot".format(
                        args.name.decode('utf-8')))
            except libcephfs.Error as e:
                set_exit_code_msg(e.get_error_code(), "error while deleting "
                                  "'{}'".format(snap_dir.decode('utf-8')))
        else:
            set_exit_code_msg(errno.EINVAL, "snapshot can only be created or "
                              "deleted; check - help snap")

    def do_help(self, line):
        """
        Get details about a command.
            Usage: help <cmd> - for a specific command
                   help all - for all the commands
        """
        if line == 'all':
            for k in dir(self):
                if k.startswith('do_'):
                    poutput('-' * 80)
                    super().do_help(k[3:])
            return
        parser = self.create_argparser(line)
        if parser:
            parser.print_help()
        else:
            super().do_help(line)

    def complete_stat(self, text, line, begidx, endidx):
        """
        auto complete of file name.
        """
        return self.complete_filenames(text, line, begidx, endidx)

    stat_parser = argparse.ArgumentParser(
        description='Display file or file system status')
    stat_parser.add_argument('paths', type=str, help='file paths',
                             action=path_to_bytes, nargs='+')

    @with_argparser(stat_parser)
    def do_stat(self, args):
        """
        Display file or file system status
        """
        for path in args.paths:
            try:
                stat = cephfs.stat(path)
                atime = stat.st_atime.isoformat(' ')
                mtime = stat.st_mtime.isoformat(' ')
                ctime = stat.st_mtime.isoformat(' ')

                poutput("File: {}\nSize: {:d}\nBlocks: {:d}\nIO Block: {:d}\n"
                        "Device: {:d}\tInode: {:d}\tLinks: {:d}\nPermission: "
                        "{:o}/{}\tUid: {:d}\tGid: {:d}\nAccess: {}\nModify: "
                        "{}\nChange: {}".format(path.decode('utf-8'),
                                                stat.st_size, stat.st_blocks,
                                                stat.st_blksize, stat.st_dev,
                                                stat.st_ino, stat.st_nlink,
                                                stat.st_mode,
                                                mode_notation(stat.st_mode),
                                                stat.st_uid, stat.st_gid, atime,
                                                mtime, ctime))
            except libcephfs.Error as e:
                set_exit_code_msg(msg=e)

    setxattr_parser = argparse.ArgumentParser(
        description='Set extended attribute for a file')
    setxattr_parser.add_argument('path', type=str, action=path_to_bytes, help='Name of the file')
    setxattr_parser.add_argument('name', type=str, help='Extended attribute name')
    setxattr_parser.add_argument('value', type=str, help='Extended attribute value')

    @with_argparser(setxattr_parser)
    def do_setxattr(self, args):
        """
        Set extended attribute for a file
        """
        val_bytes = to_bytes(args.value)
        name_bytes = to_bytes(args.name)
        try:
            cephfs.setxattr(args.path, name_bytes, val_bytes, os.XATTR_CREATE)
            poutput('{} is successfully set to {}'.format(args.name, args.value))
        except libcephfs.ObjectExists:
            cephfs.setxattr(args.path, name_bytes, val_bytes, os.XATTR_REPLACE)
            poutput('{} is successfully reset to {}'.format(args.name, args.value))
        except libcephfs.Error as e:
            set_exit_code_msg(msg=e)

    getxattr_parser = argparse.ArgumentParser(
        description='Get extended attribute set for a file')
    getxattr_parser.add_argument('path', type=str, action=path_to_bytes,
                                 help='Name of the file')
    getxattr_parser.add_argument('name', type=str, help='Extended attribute name')

    @with_argparser(getxattr_parser)
    def do_getxattr(self, args):
        """
        Get extended attribute for a file
        """
        try:
            poutput('{}'.format(cephfs.getxattr(args.path,
                                to_bytes(args.name)).decode('utf-8')))
        except libcephfs.Error as e:
            set_exit_code_msg(msg=e)

    listxattr_parser = argparse.ArgumentParser(
        description='List extended attributes set for a file')
    listxattr_parser.add_argument('path', type=str, action=path_to_bytes,
                                  help='Name of the file')

    @with_argparser(listxattr_parser)
    def do_listxattr(self, args):
        """
        List extended attributes for a file
        """
        try:
            size, xattr_list = cephfs.listxattr(args.path)
            if size > 0:
                poutput('{}'.format(xattr_list.replace(b'\x00', b' ').decode('utf-8')))
            else:
                poutput('No extended attribute is set')
        except libcephfs.Error as e:
            set_exit_code_msg(msg=e)


#######################################################
#
# Following are methods that get cephfs-shell started.
#
#####################################################

def setup_cephfs(args):
    """
    Mounting a cephfs
    """
    global cephfs
    try:
        cephfs = libcephfs.LibCephFS(conffile='')
        cephfs.mount(filesystem_name=args.fs)
    except libcephfs.ObjectNotFound as e:
        print('couldn\'t find ceph configuration not found')
        sys.exit(e.get_error_code())
    except libcephfs.Error as e:
        print(e)
        sys.exit(e.get_error_code())


def str_to_bool(val):
    """
    Return corresponding bool values for strings like 'true' or 'false'.
    """
    if not isinstance(val, str):
        return val

    val = val.replace('\n', '')
    if val.lower() in ['true', 'yes']:
        return True
    elif val.lower() in ['false', 'no']:
        return False
    else:
        return val


def read_shell_conf(shell, shell_conf_file):
    import configparser

    sec = 'cephfs-shell'
    opts = []
    if LooseVersion(cmd2_version) >= LooseVersion("0.10.0"):
        for attr in shell.settables.keys():
            opts.append(attr)
    else:
        if LooseVersion(cmd2_version) <= LooseVersion("0.9.13"):
            # hardcoding options for 0.7.9 because -
            # 1. we use cmd2 v0.7.9 with teuthology and
            # 2. there's no way distinguish between a shell setting and shell
            #    object attribute until v0.10.0
            opts = ['abbrev', 'autorun_on_edit', 'colors',
                    'continuation_prompt', 'debug', 'echo', 'editor',
                    'feedback_to_output', 'locals_in_py', 'prompt', 'quiet',
                    'timing']
        elif LooseVersion(cmd2_version) >= LooseVersion("0.9.23"):
            opts.append('allow_style')
        # no equivalent option was defined by cmd2.
        else:
            pass

    # default and only section in our conf file.
    cp = configparser.ConfigParser(default_section=sec, strict=False)
    cp.read(shell_conf_file)
    for opt in opts:
        if cp.has_option(sec, opt):
            setattr(shell, opt, str_to_bool(cp.get(sec, opt)))


def get_shell_conffile_path(arg_conf=''):
    conf_filename = 'cephfs-shell.conf'
    env_var = 'CEPHFS_SHELL_CONF'

    arg_conf = '' if not arg_conf else arg_conf
    home_dir_conf = os.path.expanduser('~/.' + conf_filename)
    env_conf = os.environ[env_var] if env_var in os.environ else ''

    # here's the priority by which conf gets read.
    for path in (arg_conf, env_conf, home_dir_conf):
        if os.path.isfile(path):
            return path
    else:
        return ''


def manage_args():
    main_parser = argparse.ArgumentParser(description='')
    main_parser.add_argument('-b', '--batch', action='store',
                             help='Path to CephFS shell script/batch file'
                                  'containing CephFS shell commands',
                             type=str)
    main_parser.add_argument('-c', '--config', action='store',
                             help='Path to Ceph configuration file.',
                             type=str)
    main_parser.add_argument('-f', '--fs', action='store',
                             help='Name of filesystem to mount.',
                             type=str)
    main_parser.add_argument('-t', '--test', action='store',
                             help='Test against transcript(s) in FILE',
                             nargs='+')
    main_parser.add_argument('commands', nargs='*', help='Comma delimited '
                             'commands. The shell executes the given command '
                             'and quits immediately with the return value of '
                             'command. In case no commands are provided, the '
                             'shell is launched.', default=[])

    args = main_parser.parse_args()
    args.exe_and_quit = False    # Execute and quit, don't launch the shell.

    if args.batch:
        if LooseVersion(cmd2_version) <= LooseVersion("0.9.13"):
            args.commands = ['load ' + args.batch, ',quit']
        else:
            args.commands = ['run_script ' + args.batch, ',quit']
    if args.test:
        args.commands.extend(['-t,'] + [arg + ',' for arg in args.test])
    if not args.batch and len(args.commands) > 0:
        args.exe_and_quit = True

    manage_sys_argv(args)

    return args


def manage_sys_argv(args):
    exe = sys.argv[0]
    sys.argv.clear()
    sys.argv.append(exe)
    sys.argv.extend([i.strip() for i in ' '.join(args.commands).split(',')])

    setup_cephfs(args)


def execute_cmd_args(args):
    """
    Launch a shell session if no arguments were passed, else just execute
    the given argument as a shell command and exit the shell session
    immediately at (last) command's termination with the (last) command's
    return value.
    """
    if not args.exe_and_quit:
        return shell.cmdloop()
    return execute_cmds_and_quit(args)


def execute_cmds_and_quit(args):
    """
    Multiple commands might be passed separated by commas, feed onecmd()
    one command at a time.
    """
    # do_* methods triggered by cephfs-shell commands return None when they
    # complete running successfully. Until 0.9.6, shell.onecmd() returned this
    # value to indicate whether the execution of the commands should stop, but
    # since 0.9.7 it returns the return value of do_* methods only if it's
    # not None. When it is None it returns False instead of None.
    if LooseVersion(cmd2_version) <= LooseVersion("0.9.6"):
        stop_exec_val = None
    else:
        stop_exec_val = False

    args_to_onecmd = ''
    if len(args.commands) <= 1:
        args.commands = args.commands[0].split(' ')
    for cmdarg in args.commands:
        if ',' in cmdarg:
            args_to_onecmd += ' ' + cmdarg[0:-1]
            onecmd_retval = shell.onecmd(args_to_onecmd)
            # if the curent command failed, let's abort the execution of
            # series of commands passed.
            if onecmd_retval is not stop_exec_val:
                return onecmd_retval
            if shell.exit_code != 0:
                return shell.exit_code

            args_to_onecmd = ''
            continue

        args_to_onecmd += ' ' + cmdarg
    return shell.onecmd(args_to_onecmd)


if __name__ == '__main__':
    args = manage_args()

    shell = CephFSShell()
    # TODO: perhaps, we should add an option to pass ceph.conf?
    read_shell_conf(shell, get_shell_conffile_path(args.config))
    # XXX: setting shell.exit_code to zero so that in case there are no errors
    # and exceptions, it is not set by any method or function of cephfs-shell
    # and return values from shell.cmdloop() or shell.onecmd() is not an
    # integer, we can treat it as the return value of cephfs-shell.
    shell.exit_code = 0

    retval = execute_cmd_args(args)
    sys.exit(retval if retval else shell.exit_code)