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sankalpa_fsc.py
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sankalpa_fsc.py
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#!/usr/bin/env python
# Copyright (C) 2001 Jeff Epler <[email protected]>
# Copyright (C) 2006 Csaba Henk <[email protected]>
#
# This program can be distributed under the terms of the GNU LGPL.
# See the file COPYING.
#
from grpc.beta import implementations
import errno
import sankalpa_fs_pb2
import os, sys
from errno import *
from stat import *
import fcntl
# pull in some spaghetti to make this stuff work without fuse-py being installed
import tempfile
import posix
import shutil
from sys import platform as _platform
try:
import _find_fuse_parts
except ImportError:
pass
import fuse
from fuse import Fuse
stub = None
mount_point = None
root = None
transaction_dir = None
_stream_packet_size = 64 * 1024 # TCP packet size
_stream_packet_size -= 60 # maximum TCP header size
_stream_packet_size -= 192 # maximum IPv4 header size
_stream_packet_size -= 24 # Ethernet header size
_TIMEOUT_SECONDS = 30
if not hasattr(fuse, '__version__'):
raise RuntimeError, \
"your fuse-py doesn't know of fuse.__version__, probably it's too old."
fuse.fuse_python_api = (0, 2)
fuse.feature_assert('stateful_files', 'has_init')
def flag2mode(flags):
md = {os.O_RDONLY: 'r', os.O_WRONLY: 'w', os.O_RDWR: 'w+'}
m = md[flags & (os.O_RDONLY | os.O_WRONLY | os.O_RDWR)]
if flags | os.O_APPEND:
m = m.replace('w', 'a', 1)
return m
def _full_path(base_path, relative_path):
if relative_path.startswith('/'):
relative_path = relative_path[1:]
return os.path.join(base_path, relative_path)
class Xmp(Fuse):
def __init__(self, *args, **kw):
Fuse.__init__(self, *args, **kw)
# do stuff to set up your filesystem here, if you want
#import thread
#thread.start_new_thread(self.mythread, ())
self.root = '/'
# def mythread(self):
#
# """
# The beauty of the FUSE python implementation is that with the python interp
# running in foreground, you can have threads
# """
# print "mythread: started"
# while 1:
# time.sleep(120)
# print "mythread: ticking"
def getattr(self, path):
print '****************************************** getattr %s' % path
stat = stub.getattr(sankalpa_fs_pb2.Path(path=path), _TIMEOUT_SECONDS)
if stat.status != 0:
print '****************************************** getattr status != 0 %s' % stat.status
raise OSError(stat.status,"OSError", path)
print '****************************************** server_stat.st_size %s' % stat.st_size
return posix.stat_result((stat.st_mode, stat.st_ino, stat.st_dev, stat.st_nlink, stat.st_uid, stat.st_gid,
stat.st_size, stat.st_atime, stat.st_mtime, stat.st_ctime))
#return (getattr(stat, key)) for key in ('st_mode','st_ino','st_dev','st_nlink','st_uid','st_gid',
# 'st_size','st_atime','st_mtime','st_ctime'))
# return os.lstat("." + path)
# 'st_dev','st_ino',
def readlink(self, path):
return os.readlink("." + path)
def readdir(self, path, offset):
print '****************************************** readdir %s' % path
direntries = stub.readdir(sankalpa_fs_pb2.Path(path=path), _TIMEOUT_SECONDS)
if direntries.status != 0:
print '****************************************** readdir status != 0 %s' % direntries.status
raise OSError(direntries.status, "OSError", path)
for e in direntries.dir:
print '****************************************** direntry %s' % e
yield fuse.Direntry(e)
# for e in os.listdir("." + path):
# yield fuse.Direntry(e)
def unlink(self, path):
print '****************************************** unlink %s' % path
status = stub.delete(sankalpa_fs_pb2.Path(path=path), _TIMEOUT_SECONDS).status
if status == 0:
return status
else:
raise OSError(status, "OSError", path)
def rmdir(self, path):
print '****************************************** rmdir %s' % path
status = stub.rmdir(sankalpa_fs_pb2.Path(path=path), _TIMEOUT_SECONDS).status
if status == 0:
return status
else:
raise OSError(status, "OSError", path)
# os.rmdir("." + path)
def symlink(self, path, path1):
os.symlink(path, "." + path1)
def rename(self, path, path1):
print '****************************************** rename src %s dst %s' % (path, path1)
status = stub.rename(sankalpa_fs_pb2.SrcDst(src=path,dst=path1), _TIMEOUT_SECONDS).status
if status == 0:
return status
else:
raise OSError(status, "OSError", path)
#os.rename("." + path, "." + path1)
def link(self, path, path1):
os.link("." + path, "." + path1)
def chmod(self, path, mode):
os.chmod("." + path, mode)
def chown(self, path, user, group):
os.chown("." + path, user, group)
def truncate(self, path, len):
print '********** File System truncate ************'
pid = fuse.FuseGetContext()['pid']
print '********** File System truncate pid %s ' % pid
f = open(_full_path(transaction_dir,path + '.' + str(pid) + '.swp' ), "a")
f.truncate(len)
f.close()
def mknod(self, path, mode, dev):
os.mknod("." + path, mode, dev)
def mkdir(self, path, mode):
status = stub.mkdir(sankalpa_fs_pb2.Path(path=path), _TIMEOUT_SECONDS).status
if status == 0:
return status
else:
raise OSError(status, "OSError", path)
#os.mkdir("." + path, mode)
def utime(self, path, times):
os.utime("." + path, times)
# The following utimens method would do the same as the above utime method.
# We can't make it better though as the Python stdlib doesn't know of
# subsecond preciseness in acces/modify times.
#
# def utimens(self, path, ts_acc, ts_mod):
# os.utime("." + path, (ts_acc.tv_sec, ts_mod.tv_sec))
def access(self, path, mode):
if not os.access("." + path, mode):
return -EACCES
# This is how we could add stub extended attribute handlers...
# (We can't have ones which aptly delegate requests to the underlying fs
# because Python lacks a standard xattr interface.)
#
# def getxattr(self, path, name, size):
# val = name.swapcase() + '@' + path
# if size == 0:
# # We are asked for size of the value.
# return len(val)
# return val
#
# def listxattr(self, path, size):
# # We use the "user" namespace to please XFS utils
# aa = ["user." + a for a in ("foo", "bar")]
# if size == 0:
# # We are asked for size of the attr list, ie. joint size of attrs
# # plus null separators.
# return len("".join(aa)) + len(aa)
# return aa
def statfs(self):
"""
Should return an object with statvfs attributes (f_bsize, f_frsize...).
Eg., the return value of os.statvfs() is such a thing (since py 2.2).
If you are not reusing an existing statvfs object, start with
fuse.StatVFS(), and define the attributes.
To provide usable information (ie., you want sensible df(1)
output, you are suggested to specify the following attributes:
- f_bsize - preferred size of file blocks, in bytes
- f_frsize - fundamental size of file blcoks, in bytes
[if you have no idea, use the same as blocksize]
- f_blocks - total number of blocks in the filesystem
- f_bfree - number of free blocks
- f_files - total number of file inodes
- f_ffree - nunber of free file inodes
"""
return os.statvfs(".")
def fsinit(self):
os.chdir(self.root)
class XmpFile(object):
def get_server_mtime(self, proto_path):
# pdb.set_trace()
mt = stub.get_mtime(proto_path, _TIMEOUT_SECONDS).mtime
print '********************************Server_mtime in get server mt %s' % mt
return mt
def get_client_mtime(self, path):
try:
client_mtime = os.stat(path).st_mtime
except OSError as ose:
if ose.errno == errno.ENOENT:
client_mtime = 0
return client_mtime
def get_remote_file(self, proto_path):
# TODO: incremental updates with rsync
temp_filename = None
with tempfile.NamedTemporaryFile(delete=False, dir=transaction_dir) as temp:
temp_filename = temp.name
for cont in stub.get_file_contents(proto_path, _TIMEOUT_SECONDS):
temp.write(cont.content)
temp.flush()
os.fsync(temp.fileno())
return temp_filename
def update_cache(self, cache_path, server_mtime, proto_path, cache_mtime):
print '***********************************cache_mtime %s' % cache_mtime
if float(str(server_mtime)) > float(str(cache_mtime)):
print '***********************************Fetching from server '
temp_filename = self.get_remote_file(proto_path)
# keep the client mtime in sync with server due to
# network delays
os.utime(temp_filename, (os.stat(temp_filename).st_atime, server_mtime))
os.rename(temp_filename, cache_path)
def __init__(self, path, flags, *mode):
# To find whether the file is modified
self.isModified = False
self.pid = fuse.FuseGetContext()['pid']
print '****************************************** OPEN'
print '***********************************Path %s' % path
print '***********************************flags %s' % flags
print '***********************************pid %s' % self.pid
proto_path = sankalpa_fs_pb2.Path(path=path)
#getting server mtime
server_mtime = self.get_server_mtime(proto_path)
cache_path = _full_path(root, path)
transaction_path = _full_path(transaction_dir, path + '.' + str(self.pid) + '.swp')
cache_mtime = self.get_client_mtime(cache_path)
print '********************************Server_mtime %s' % server_mtime
#creating dir structures
try:
os.makedirs(os.path.dirname(cache_path))
os.makedirs(os.path.dirname(transaction_path))
except OSError as ose:
if ose.errno == 17:
pass
else:
raise ose
if server_mtime != 0:
#File is available in server
self.update_cache(cache_path, server_mtime, proto_path, cache_mtime)
print '****************************************** Updated cache'
else:
#file is not available in server
self.isModified = True
if flags == os.O_RDONLY:
#return transaction fd
print '****************************************** Read only'
self.file = os.fdopen(os.open(cache_path, flags, *mode),
flag2mode(flags))
else:
print '****************************************** Not Read only'
if server_mtime != 0:
shutil.copy(cache_path,transaction_path)
print '****************************************** shutil copy'
self.file = os.fdopen(os.open(transaction_path, flags, *mode),
flag2mode(flags))
print '****************************************** After fd open'
self.fd = self.file.fileno()
self.cache_path = cache_path
self.transaction_path = transaction_path
self.path = path
def read(self, length, offset):
self.file.seek(offset)
return self.file.read(length)
def write(self, buf, offset):
self.file.seek(offset)
self.file.write(buf)
self.isModified = True
return len(buf)
def read_file_contents(self):
print '********** read_file_contents ************'
yield sankalpa_fs_pb2.Content(content=self.path)
with open(self.transaction_path, 'r') as fo:
while True:
string_stream = fo.read(_stream_packet_size)
if string_stream:
yield sankalpa_fs_pb2.Content(content=string_stream)
else:
break
def update_remote_file(self):
print '********** update_remote_file ************'
content_iter = self.read_file_contents()
ack = stub.update_file(content_iter, _TIMEOUT_SECONDS)
if ack.file_path != self.path or ack.num_bytes != os.stat(self.transaction_path).st_size:
print '********** File Update Error ************'
raise OSError("File Update Error")
else:
# Setting the mtime in client to reflect the server
# This avoid a fetch call after every update
print '********** File Update mtime form server ************ %s' % ack.server_mtime.mtime
os.utime(self.transaction_path, (os.stat(self.transaction_path).st_atime, ack.server_mtime.mtime))
self.fsync('linux' in _platform.lower())
os.rename(self.transaction_path, self.cache_path)
def release(self, flags):
print '********** RELEASE ************'
print '********** isModified %s ' % self.isModified
if self.isModified:
self.update_remote_file()
self.isModified = False
self.file.close()
def _fflush(self):
if 'w' in self.file.mode or 'a' in self.file.mode:
self.file.flush()
def fsync(self, isfsyncfile):
self._fflush()
if isfsyncfile and hasattr(os, 'fdatasync'):
os.fdatasync(self.fd)
else:
os.fsync(self.fd)
def flush(self):
self._fflush()
# cf. xmp_flush() in fusexmp_fh.c
os.close(os.dup(self.fd))
def fgetattr(self):
return os.fstat(self.fd)
def ftruncate(self, len):
print '********** File ftruncate ************'
self.file.truncate(len)
self.isModified = True
def lock(self, cmd, owner, **kw):
# The code here is much rather just a demonstration of the locking
# API than something which actually was seen to be useful.
# Advisory file locking is pretty messy in Unix, and the Python
# interface to this doesn't make it better.
# We can't do fcntl(2)/F_GETLK from Python in a platfrom independent
# way. The following implementation *might* work under Linux.
#
# if cmd == fcntl.F_GETLK:
# import struct
#
# lockdata = struct.pack('hhQQi', kw['l_type'], os.SEEK_SET,
# kw['l_start'], kw['l_len'], kw['l_pid'])
# ld2 = fcntl.fcntl(self.fd, fcntl.F_GETLK, lockdata)
# flockfields = ('l_type', 'l_whence', 'l_start', 'l_len', 'l_pid')
# uld2 = struct.unpack('hhQQi', ld2)
# res = {}
# for i in xrange(len(uld2)):
# res[flockfields[i]] = uld2[i]
#
# return fuse.Flock(**res)
# Convert fcntl-ish lock parameters to Python's weird
# lockf(3)/flock(2) medley locking API...
op = { fcntl.F_UNLCK : fcntl.LOCK_UN,
fcntl.F_RDLCK : fcntl.LOCK_SH,
fcntl.F_WRLCK : fcntl.LOCK_EX }[kw['l_type']]
if cmd == fcntl.F_GETLK:
return -EOPNOTSUPP
elif cmd == fcntl.F_SETLK:
if op != fcntl.LOCK_UN:
op |= fcntl.LOCK_NB
elif cmd == fcntl.F_SETLKW:
pass
else:
return -EINVAL
fcntl.lockf(self.fd, op, kw['l_start'], kw['l_len'])
def main(self, *a, **kw):
self.file_class = self.XmpFile
return Fuse.main(self, *a, **kw)
def main():
global stub, mount_point, root, transaction_dir
channel = implementations.insecure_channel('pc-c220m4-r03-19.wisc.cloudlab.us', 50051)
stub = sankalpa_fs_pb2.beta_create_SankalpaFS_stub(channel)
usage = """
Userspace nullfs-alike: mirror the filesystem tree from some point on.
""" + Fuse.fusage
server = Xmp(version="%prog " + fuse.__version__,
usage=usage,
dash_s_do='setsingle')
server.parser.add_option(mountopt="root", metavar="PATH", default='/',
help="mirror filesystem from under PATH [default: %default]")
server.parse(values=server, errex=1)
mount_point = server.fuse_args.mountpoint
root = server.root
transaction_dir = os.path.join(root, '..', '.transactions')
try:
os.makedirs(transaction_dir)
except OSError as ose:
if ose.errno == 17:
pass
else:
raise ose
try:
if server.fuse_args.mount_expected():
os.chdir(server.root)
except OSError:
print >> sys.stderr, "can't enter root of underlying filesystem"
sys.exit(1)
server.main()
if __name__ == '__main__':
main()