Synnefo » Pithos

# Copyright (c) 2008 Giorgos Verigakis <verigak@gmail.com>

# 

# Permission to use, copy, modify, and distribute this software for any

# purpose with or without fee is hereby granted, provided that the above

# copyright notice and this permission notice appear in all copies.

# 

# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

from __future__ import division

from ctypes import *

from ctypes.util import find_library

from errno import *

from functools import partial

from os import strerror

from platform import machine, system

from stat import S_IFDIR

from traceback import print_exc

class c_timespec(Structure):

    _fields_ = [('tv_sec', c_long), ('tv_nsec', c_long)]

class c_utimbuf(Structure):

    _fields_ = [('actime', c_timespec), ('modtime', c_timespec)]

class c_stat(Structure):

    pass    # Platform dependent

_system = system()

if _system in ('Darwin', 'FreeBSD'):

    _libiconv = CDLL(find_library("iconv"), RTLD_GLOBAL)     # libfuse dependency

    ENOTSUP = 45

    c_dev_t = c_int32

    c_fsblkcnt_t = c_ulong

    c_fsfilcnt_t = c_ulong

    c_gid_t = c_uint32

    c_mode_t = c_uint16

    c_off_t = c_int64

    c_pid_t = c_int32

    c_uid_t = c_uint32

    setxattr_t = CFUNCTYPE(c_int, c_char_p, c_char_p, POINTER(c_byte),

        c_size_t, c_int, c_uint32)

    getxattr_t = CFUNCTYPE(c_int, c_char_p, c_char_p, POINTER(c_byte),

        c_size_t, c_uint32)

    c_stat._fields_ = [

        ('st_dev', c_dev_t),

        ('st_ino', c_uint32),

        ('st_mode', c_mode_t),

        ('st_nlink', c_uint16),

        ('st_uid', c_uid_t),

        ('st_gid', c_gid_t),

        ('st_rdev', c_dev_t),

        ('st_atimespec', c_timespec),

        ('st_mtimespec', c_timespec),

        ('st_ctimespec', c_timespec),

        ('st_size', c_off_t),

        ('st_blocks', c_int64),

        ('st_blksize', c_int32)]

elif _system == 'Linux':

    ENOTSUP = 95

    c_dev_t = c_ulonglong

    c_fsblkcnt_t = c_ulonglong

    c_fsfilcnt_t = c_ulonglong

    c_gid_t = c_uint

    c_mode_t = c_uint

    c_off_t = c_longlong

    c_pid_t = c_int

    c_uid_t = c_uint

    setxattr_t = CFUNCTYPE(c_int, c_char_p, c_char_p, POINTER(c_byte), c_size_t, c_int)

    getxattr_t = CFUNCTYPE(c_int, c_char_p, c_char_p, POINTER(c_byte), c_size_t)

    _machine = machine()

    if _machine == 'x86_64':

        c_stat._fields_ = [

            ('st_dev', c_dev_t),

            ('st_ino', c_ulong),

            ('st_nlink', c_ulong),

            ('st_mode', c_mode_t),

            ('st_uid', c_uid_t),

            ('st_gid', c_gid_t),

            ('__pad0', c_int),

            ('st_rdev', c_dev_t),

            ('st_size', c_off_t),

            ('st_blksize', c_long),

            ('st_blocks', c_long),

            ('st_atimespec', c_timespec),

            ('st_mtimespec', c_timespec),

            ('st_ctimespec', c_timespec)]

    elif _machine == 'ppc':

        c_stat._fields_ = [

            ('st_dev', c_dev_t),

            ('st_ino', c_ulonglong),

            ('st_mode', c_mode_t),

            ('st_nlink', c_uint),

            ('st_uid', c_uid_t),

            ('st_gid', c_gid_t),

            ('st_rdev', c_dev_t),

            ('__pad2', c_ushort),

            ('st_size', c_off_t),

            ('st_blksize', c_long),

            ('st_blocks', c_longlong),

            ('st_atimespec', c_timespec),

            ('st_mtimespec', c_timespec),

            ('st_ctimespec', c_timespec)]

    else:

        # i686, use as fallback for everything else

        c_stat._fields_ = [

            ('st_dev', c_dev_t),

            ('__pad1', c_ushort),

            ('__st_ino', c_ulong),

            ('st_mode', c_mode_t),

            ('st_nlink', c_uint),

            ('st_uid', c_uid_t),

            ('st_gid', c_gid_t),

            ('st_rdev', c_dev_t),

            ('__pad2', c_ushort),

            ('st_size', c_off_t),

            ('st_blksize', c_long),

            ('st_blocks', c_longlong),

            ('st_atimespec', c_timespec),

            ('st_mtimespec', c_timespec),

            ('st_ctimespec', c_timespec),

            ('st_ino', c_ulonglong)]

else:

    raise NotImplementedError('%s is not supported.' % _system)

class c_statvfs(Structure):

    _fields_ = [

        ('f_bsize', c_ulong),

        ('f_frsize', c_ulong),

        ('f_blocks', c_fsblkcnt_t),

        ('f_bfree', c_fsblkcnt_t),

        ('f_bavail', c_fsblkcnt_t),

        ('f_files', c_fsfilcnt_t),

        ('f_ffree', c_fsfilcnt_t),

        ('f_favail', c_fsfilcnt_t)]

if _system == 'FreeBSD':

    c_fsblkcnt_t = c_uint64

    c_fsfilcnt_t = c_uint64

    setxattr_t = CFUNCTYPE(c_int, c_char_p, c_char_p, POINTER(c_byte), c_size_t, c_int)

    getxattr_t = CFUNCTYPE(c_int, c_char_p, c_char_p, POINTER(c_byte), c_size_t)

    class c_statvfs(Structure):

        _fields_ = [

            ('f_bavail', c_fsblkcnt_t),

            ('f_bfree', c_fsblkcnt_t),

            ('f_blocks', c_fsblkcnt_t),

            ('f_favail', c_fsfilcnt_t),

            ('f_ffree', c_fsfilcnt_t),

            ('f_files', c_fsfilcnt_t),

            ('f_bsize', c_ulong),

            ('f_flag', c_ulong),

            ('f_frsize', c_ulong)]

class fuse_file_info(Structure):

    _fields_ = [

        ('flags', c_int),

        ('fh_old', c_ulong),

        ('writepage', c_int),

        ('direct_io', c_uint, 1),

        ('keep_cache', c_uint, 1),

        ('flush', c_uint, 1),

        ('padding', c_uint, 29),

        ('fh', c_uint64),

        ('lock_owner', c_uint64)]

class fuse_context(Structure):

    _fields_ = [

        ('fuse', c_voidp),

        ('uid', c_uid_t),

        ('gid', c_gid_t),

        ('pid', c_pid_t),

        ('private_data', c_voidp)]

class fuse_operations(Structure):

    _fields_ = [

        ('getattr', CFUNCTYPE(c_int, c_char_p, POINTER(c_stat))),

        ('readlink', CFUNCTYPE(c_int, c_char_p, POINTER(c_byte), c_size_t)),

        ('getdir', c_voidp),    # Deprecated, use readdir

        ('mknod', CFUNCTYPE(c_int, c_char_p, c_mode_t, c_dev_t)),

        ('mkdir', CFUNCTYPE(c_int, c_char_p, c_mode_t)),

        ('unlink', CFUNCTYPE(c_int, c_char_p)),

        ('rmdir', CFUNCTYPE(c_int, c_char_p)),

        ('symlink', CFUNCTYPE(c_int, c_char_p, c_char_p)),

        ('rename', CFUNCTYPE(c_int, c_char_p, c_char_p)),

        ('link', CFUNCTYPE(c_int, c_char_p, c_char_p)),

        ('chmod', CFUNCTYPE(c_int, c_char_p, c_mode_t)),

        ('chown', CFUNCTYPE(c_int, c_char_p, c_uid_t, c_gid_t)),

        ('truncate', CFUNCTYPE(c_int, c_char_p, c_off_t)),

        ('utime', c_voidp),     # Deprecated, use utimens

        ('open', CFUNCTYPE(c_int, c_char_p, POINTER(fuse_file_info))),

        ('read', CFUNCTYPE(c_int, c_char_p, POINTER(c_byte), c_size_t, c_off_t,

            POINTER(fuse_file_info))),

        ('write', CFUNCTYPE(c_int, c_char_p, POINTER(c_byte), c_size_t, c_off_t,

            POINTER(fuse_file_info))),

        ('statfs', CFUNCTYPE(c_int, c_char_p, POINTER(c_statvfs))),

        ('flush', CFUNCTYPE(c_int, c_char_p, POINTER(fuse_file_info))),

        ('release', CFUNCTYPE(c_int, c_char_p, POINTER(fuse_file_info))),

        ('fsync', CFUNCTYPE(c_int, c_char_p, c_int, POINTER(fuse_file_info))),

        ('setxattr', setxattr_t),

        ('getxattr', getxattr_t),

        ('listxattr', CFUNCTYPE(c_int, c_char_p, POINTER(c_byte), c_size_t)),

        ('removexattr', CFUNCTYPE(c_int, c_char_p, c_char_p)),

        ('opendir', CFUNCTYPE(c_int, c_char_p, POINTER(fuse_file_info))),

        ('readdir', CFUNCTYPE(c_int, c_char_p, c_voidp, CFUNCTYPE(c_int, c_voidp,

            c_char_p, POINTER(c_stat), c_off_t), c_off_t, POINTER(fuse_file_info))),

        ('releasedir', CFUNCTYPE(c_int, c_char_p, POINTER(fuse_file_info))),

        ('fsyncdir', CFUNCTYPE(c_int, c_char_p, c_int, POINTER(fuse_file_info))),

        ('init', CFUNCTYPE(c_voidp, c_voidp)),

        ('destroy', CFUNCTYPE(c_voidp, c_voidp)),

        ('access', CFUNCTYPE(c_int, c_char_p, c_int)),

        ('create', CFUNCTYPE(c_int, c_char_p, c_mode_t, POINTER(fuse_file_info))),

        ('ftruncate', CFUNCTYPE(c_int, c_char_p, c_off_t, POINTER(fuse_file_info))),

        ('fgetattr', CFUNCTYPE(c_int, c_char_p, POINTER(c_stat),

            POINTER(fuse_file_info))),

        ('lock', CFUNCTYPE(c_int, c_char_p, POINTER(fuse_file_info), c_int, c_voidp)),

        ('utimens', CFUNCTYPE(c_int, c_char_p, POINTER(c_utimbuf))),

        ('bmap', CFUNCTYPE(c_int, c_char_p, c_size_t, POINTER(c_ulonglong)))]

def time_of_timespec(ts):

    return ts.tv_sec + ts.tv_nsec / 10 ** 9

def set_st_attrs(st, attrs):

    for key, val in attrs.items():

        if key in ('st_atime', 'st_mtime', 'st_ctime'):

            timespec = getattr(st, key + 'spec')

            timespec.tv_sec = int(val)

            timespec.tv_nsec = int((val - timespec.tv_sec) * 10 ** 9)

        elif hasattr(st, key):

            setattr(st, key, val)

_libfuse_path = find_library('fuse')

if not _libfuse_path:

    raise EnvironmentError('Unable to find libfuse')

_libfuse = CDLL(_libfuse_path)

_libfuse.fuse_get_context.restype = POINTER(fuse_context)

def fuse_get_context():

    """Returns a (uid, gid, pid) tuple"""

    ctxp = _libfuse.fuse_get_context()

    ctx = ctxp.contents

    return ctx.uid, ctx.gid, ctx.pid

class FuseOSError(OSError):

    def __init__(self, errno):

        super(FuseOSError, self).__init__(errno, strerror(errno))

class FUSE(object):

    """This class is the lower level interface and should not be subclassed

       under normal use. Its methods are called by fuse.

       Assumes API version 2.6 or later."""

    def __init__(self, operations, mountpoint, raw_fi=False, **kwargs):

        """Setting raw_fi to True will cause FUSE to pass the fuse_file_info

           class as is to Operations, instead of just the fh field.

           This gives you access to direct_io, keep_cache, etc."""

        self.operations = operations

        self.raw_fi = raw_fi

        args = ['fuse']

        if kwargs.pop('foreground', False):

            args.append('-f')

        if kwargs.pop('debug', False):

            args.append('-d')

        if kwargs.pop('nothreads', False):

            args.append('-s')

        kwargs.setdefault('fsname', operations.__class__.__name__)

        args.append('-o')

        args.append(','.join(key if val == True else '%s=%s' % (key, val)

            for key, val in kwargs.items()))

        args.append(mountpoint)

        argv = (c_char_p * len(args))(*args)

        fuse_ops = fuse_operations()

        for name, prototype in fuse_operations._fields_:

            if prototype != c_voidp and getattr(operations, name, None):

                op = partial(self._wrapper_, getattr(self, name))

                setattr(fuse_ops, name, prototype(op))

        err = _libfuse.fuse_main_real(len(args), argv, pointer(fuse_ops),

            sizeof(fuse_ops), None)            

        del self.operations     # Invoke the destructor

        if err:

            raise RuntimeError(err)

    def _wrapper_(self, func, *args, **kwargs):

        """Decorator for the methods that follow"""

        try:

            return func(*args, **kwargs) or 0

        except OSError, e:

            return -(e.errno or EFAULT)

        except:

            print_exc()

            return -EFAULT

    def getattr(self, path, buf):

        return self.fgetattr(path, buf, None)

    def readlink(self, path, buf, bufsize):

        ret = self.operations('readlink', path)

        data = create_string_buffer(ret[:bufsize - 1])

        memmove(buf, data, len(data))

        return 0

    def mknod(self, path, mode, dev):

        return self.operations('mknod', path, mode, dev)

    def mkdir(self, path, mode):

        return self.operations('mkdir', path, mode)

    def unlink(self, path):

        return self.operations('unlink', path)

    def rmdir(self, path):

        return self.operations('rmdir', path)

    def symlink(self, source, target):

        return self.operations('symlink', target, source)

    def rename(self, old, new):

        return self.operations('rename', old, new)

    def link(self, source, target):

        return self.operations('link', target, source)

    def chmod(self, path, mode):

        return self.operations('chmod', path, mode)

    def chown(self, path, uid, gid):

        # Check if any of the arguments is a -1 that has overflowed

        if c_uid_t(uid + 1).value == 0:

            uid = -1

        if c_gid_t(gid + 1).value == 0:

            gid = -1

        return self.operations('chown', path, uid, gid)

    def truncate(self, path, length):

        return self.operations('truncate', path, length)

    def open(self, path, fip):

        fi = fip.contents

        if self.raw_fi:

            return self.operations('open', path, fi)

        else:

            fi.fh = self.operations('open', path, fi.flags)

            return 0

    def read(self, path, buf, size, offset, fip):

        fh = fip.contents if self.raw_fi else fip.contents.fh

        ret = self.operations('read', path, size, offset, fh)

        if not ret:

            return 0

        data = create_string_buffer(ret[:size], size)

        memmove(buf, data, size)

        return size

    def write(self, path, buf, size, offset, fip):

        data = string_at(buf, size)

        fh = fip.contents if self.raw_fi else fip.contents.fh

        return self.operations('write', path, data, offset, fh)

    def statfs(self, path, buf):

        stv = buf.contents

        attrs = self.operations('statfs', path)

        for key, val in attrs.items():

            if hasattr(stv, key):

                setattr(stv, key, val)

        return 0

    def flush(self, path, fip):

        fh = fip.contents if self.raw_fi else fip.contents.fh

        return self.operations('flush', path, fh)

    def release(self, path, fip):

        fh = fip.contents if self.raw_fi else fip.contents.fh

        return self.operations('release', path, fh)

    def fsync(self, path, datasync, fip):

        fh = fip.contents if self.raw_fi else fip.contents.fh

        return self.operations('fsync', path, datasync, fh)

    def setxattr(self, path, name, value, size, options, *args):

        data = string_at(value, size)

        return self.operations('setxattr', path, name, data, options, *args)

    def getxattr(self, path, name, value, size, *args):

        ret = self.operations('getxattr', path, name, *args)

        retsize = len(ret)

        buf = create_string_buffer(ret, retsize)    # Does not add trailing 0

        if bool(value):

            if retsize > size:

                return -ERANGE

            memmove(value, buf, retsize)

        return retsize

    def listxattr(self, path, namebuf, size):

        ret = self.operations('listxattr', path)

        buf = create_string_buffer('\x00'.join(ret)) if ret else ''

        bufsize = len(buf)

        if bool(namebuf):

            if bufsize > size:

                return -ERANGE

            memmove(namebuf, buf, bufsize)

        return bufsize

    def removexattr(self, path, name):

        return self.operations('removexattr', path, name)

    def opendir(self, path, fip):

        # Ignore raw_fi

        fip.contents.fh = self.operations('opendir', path)

        return 0

    def readdir(self, path, buf, filler, offset, fip):

        # Ignore raw_fi

        for item in self.operations('readdir', path, fip.contents.fh):

            if isinstance(item, (str, unicode)):

                name, st, offset = item, None, 0

            else:

                name, attrs, offset = item

                if attrs:

                    st = c_stat()

                    set_st_attrs(st, attrs)

                else:

                    st = None

            if filler(buf, name, st, offset) != 0:

                break

        return 0

    def releasedir(self, path, fip):

        # Ignore raw_fi

        return self.operations('releasedir', path, fip.contents.fh)

    def fsyncdir(self, path, datasync, fip):

        # Ignore raw_fi

        return self.operations('fsyncdir', path, datasync, fip.contents.fh)

    def init(self, conn):

        return self.operations('init', '/')

    def destroy(self, private_data):

        return self.operations('destroy', '/')

    def access(self, path, amode):

        return self.operations('access', path, amode)

    def create(self, path, mode, fip):

        fi = fip.contents

        if self.raw_fi:

            return self.operations('create', path, mode, fi)

        else:

            fi.fh = self.operations('create', path, mode)

            return 0

    def ftruncate(self, path, length, fip):

        fh = fip.contents if self.raw_fi else fip.contents.fh

        return self.operations('truncate', path, length, fh)

    def fgetattr(self, path, buf, fip):

        memset(buf, 0, sizeof(c_stat))

        st = buf.contents

        fh = fip and (fip.contents if self.raw_fi else fip.contents.fh)

        attrs = self.operations('getattr', path, fh)

        set_st_attrs(st, attrs)

        return 0

    def lock(self, path, fip, cmd, lock):

        fh = fip.contents if self.raw_fi else fip.contents.fh

        return self.operations('lock', path, fh, cmd, lock)

    def utimens(self, path, buf):

        if buf:

            atime = time_of_timespec(buf.contents.actime)

            mtime = time_of_timespec(buf.contents.modtime)

            times = (atime, mtime)

        else:

            times = None

        return self.operations('utimens', path, times)

    def bmap(self, path, blocksize, idx):

        return self.operations('bmap', path, blocksize, idx)

class Operations(object):

    """This class should be subclassed and passed as an argument to FUSE on

       initialization. All operations should raise a FuseOSError exception

       on error.

       When in doubt of what an operation should do, check the FUSE header

       file or the corresponding system call man page."""

    def __call__(self, op, *args):

        if not hasattr(self, op):

            raise FuseOSError(EFAULT)

        return getattr(self, op)(*args)

    def access(self, path, amode):

        return 0

    bmap = None

    def chmod(self, path, mode):

        raise FuseOSError(EROFS)

    def chown(self, path, uid, gid):

        raise FuseOSError(EROFS)

    def create(self, path, mode, fi=None):

        """When raw_fi is False (default case), fi is None and create should

           return a numerical file handle.

           When raw_fi is True the file handle should be set directly by create

           and return 0."""

        raise FuseOSError(EROFS)

    def destroy(self, path):

        """Called on filesystem destruction. Path is always /"""

        pass

    def flush(self, path, fh):

        return 0

    def fsync(self, path, datasync, fh):

        return 0

    def fsyncdir(self, path, datasync, fh):

        return 0

    def getattr(self, path, fh=None):

        """Returns a dictionary with keys identical to the stat C structure

           of stat(2).

           st_atime, st_mtime and st_ctime should be floats.

           NOTE: There is an incombatibility between Linux and Mac OS X concerning

           st_nlink of directories. Mac OS X counts all files inside the directory,

           while Linux counts only the subdirectories."""

        if path != '/':

            raise FuseOSError(ENOENT)

        return dict(st_mode=(S_IFDIR | 0755), st_nlink=2)

    def getxattr(self, path, name, position=0):

        raise FuseOSError(ENOTSUP)

    def init(self, path):

        """Called on filesystem initialization. Path is always /

           Use it instead of __init__ if you start threads on initialization."""

        pass

    def link(self, target, source):

        raise FuseOSError(EROFS)

    def listxattr(self, path):

        return []

    lock = None

    def mkdir(self, path, mode):

        raise FuseOSError(EROFS)

    def mknod(self, path, mode, dev):

        raise FuseOSError(EROFS)

    def open(self, path, flags):

        """When raw_fi is False (default case), open should return a numerical

           file handle.

           When raw_fi is True the signature of open becomes:

               open(self, path, fi)

           and the file handle should be set directly."""

        return 0

    def opendir(self, path):

        """Returns a numerical file handle."""

        return 0

    def read(self, path, size, offset, fh):

        """Returns a string containing the data requested."""

        raise FuseOSError(EIO)

    def readdir(self, path, fh):

        """Can return either a list of names, or a list of (name, attrs, offset)

           tuples. attrs is a dict as in getattr."""

        return ['.', '..']

    def readlink(self, path):

        raise FuseOSError(ENOENT)

    def release(self, path, fh):

        return 0

    def releasedir(self, path, fh):

        return 0

    def removexattr(self, path, name):

        raise FuseOSError(ENOTSUP)

    def rename(self, old, new):

        raise FuseOSError(EROFS)

    def rmdir(self, path):

        raise FuseOSError(EROFS)

    def setxattr(self, path, name, value, options, position=0):

        raise FuseOSError(ENOTSUP)

    def statfs(self, path):

        """Returns a dictionary with keys identical to the statvfs C structure

           of statvfs(3).

           On Mac OS X f_bsize and f_frsize must be a power of 2 (minimum 512)."""

        return {}

    def symlink(self, target, source):

        raise FuseOSError(EROFS)

    def truncate(self, path, length, fh=None):

        raise FuseOSError(EROFS)

    def unlink(self, path):

        raise FuseOSError(EROFS)

    def utimens(self, path, times=None):

        """Times is a (atime, mtime) tuple. If None use current time."""

        return 0

    def write(self, path, data, offset, fh):

        raise FuseOSError(EROFS)

class LoggingMixIn:

    def __call__(self, op, path, *args):

        print '->', op, path, repr(args)

        ret = '[Unhandled Exception]'

        try:

            ret = getattr(self, op)(path, *args)

            return ret

        except OSError, e:

            ret = str(e)

            raise

        finally:

            print '<-', op, repr(ret)