#! /usr/bin/env python ''' Tahoe thin-client fuse module. Goals: - Delegate to Tahoe webapi as much as possible. - Thin as possible. - This is a proof-of-concept, not a usable product. ''' #import bindann #bindann.install_exception_handler() import sys, stat, os, errno, urllib import simplejson # FIXME: Currently uses the old, silly path-based (non-stateful) interface: import fuse fuse.fuse_python_api = (0, 1) # Use the silly path-based api for now. ### Config: TahoeConfigDir = '~/.tahoe' MagicDevNumber = 42 def main(args = sys.argv[1:]): fs = TahoeFS(os.path.expanduser(TahoeConfigDir)) fs.main() ### Utilities just for debug: def debugdeco(m): def dbmeth(self, *a, **kw): pid = self.GetContext()['pid'] print '[%d %r]\n%s%r%r' % (pid, get_cmdline(pid), m.__name__, a, kw) try: r = m(self, *a, **kw) if (type(r) is int) and (r < 0): print '-> -%s\n' % (errno.errorcode[-r],) else: repstr = repr(r)[:256] print '-> %s\n' % (repstr,) return r except: sys.excepthook(*sys.exc_info()) return dbmeth def get_cmdline(pid): f = open('/proc/%d/cmdline' % pid, 'r') args = f.read().split('\0') f.close() assert args[-1] == '' return args[:-1] class ErrnoExc (Exception): def __init__(self, eno): self.eno = eno Exception.__init__(self, errno.errorcode[eno]) @staticmethod def wrapped(meth): def wrapper(*args, **kw): try: return meth(*args, **kw) except ErrnoExc, e: return -e.eno wrapper.__name__ = meth.__name__ return wrapper ### Heart of the Matter: class TahoeFS (fuse.Fuse): def __init__(self, confdir): fuse.Fuse.__init__(self) self.confdir = confdir self.flags = 0 # FIXME: What goes here? self.multithreaded = 0 # silly path-based file handles. self.filecontents = {} # {path -> contents} self._init_url() self._init_bookmarks() def _init_url(self): f = open(os.path.join(self.confdir, 'webport'), 'r') contents = f.read() f.close() fields = contents.split(':') proto, port = fields[:2] assert proto == 'tcp' port = int(port) self.url = 'http://localhost:%d' % (port,) def _init_bookmarks(self): f = open(os.path.join(self.confdir, 'fuse-bookmarks.uri'), 'r') uri = f.read().strip() f.close() self.bookmarks = TahoeDir(self.url, uri) def _get_node(self, path): assert path.startswith('/') if path == '/': return self.bookmarks.resolve_path([]) else: parts = path.split('/')[1:] return self.bookmarks.resolve_path(parts) def _get_contents(self, path): node = self._get_node(path) contents = node.open().read() self.filecontents[path] = contents return contents @debugdeco @ErrnoExc.wrapped def getattr(self, path): node = self._get_node(path) return node.getattr() @debugdeco @ErrnoExc.wrapped def getdir(self, path): """ return: [(name, typeflag), ... ] """ node = self._get_node(path) return node.getdir() @debugdeco @ErrnoExc.wrapped def mythread(self): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def chmod(self, path, mode): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def chown(self, path, uid, gid): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def fsync(self, path, isFsyncFile): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def link(self, target, link): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def mkdir(self, path, mode): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def mknod(self, path, mode, dev_ignored): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def open(self, path, mode): IgnoredFlags = os.O_RDONLY | os.O_NONBLOCK | os.O_SYNC | os.O_LARGEFILE # Note: IgnoredFlags are all ignored! for fname in dir(os): if fname.startswith('O_'): flag = getattr(os, fname) if flag & IgnoredFlags: continue elif mode & flag: print 'Flag not supported:', fname raise ErrnoExc(errno.ENOSYS) self._get_contents(path) return 0 @debugdeco @ErrnoExc.wrapped def read(self, path, length, offset): return self._get_contents(path)[offset:length] @debugdeco @ErrnoExc.wrapped def release(self, path): del self.filecontents[path] return 0 @debugdeco @ErrnoExc.wrapped def readlink(self, path): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def rename(self, oldpath, newpath): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def rmdir(self, path): return -errno.ENOSYS #@debugdeco @ErrnoExc.wrapped def statfs(self): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def symlink ( self, targetPath, linkPath ): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def truncate(self, path, size): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def unlink(self, path): return -errno.ENOSYS @debugdeco @ErrnoExc.wrapped def utime(self, path, times): return -errno.ENOSYS class TahoeNode (object): NextInode = 0 @staticmethod def make(baseurl, uri): typefield = uri.split(':', 2)[1] if typefield.startswith('DIR'): return TahoeDir(baseurl, uri) else: return TahoeFile(baseurl, uri) def __init__(self, baseurl, uri): self.burl = baseurl self.uri = uri self.fullurl = '%s/uri/%s' % (self.burl, self.uri.replace('/', '!')) self.inode = TahoeNode.NextInode TahoeNode.NextInode += 1 def getattr(self): """ - st_mode (protection bits) - st_ino (inode number) - st_dev (device) - st_nlink (number of hard links) - st_uid (user ID of owner) - st_gid (group ID of owner) - st_size (size of file, in bytes) - st_atime (time of most recent access) - st_mtime (time of most recent content modification) - st_ctime (platform dependent; time of most recent metadata change on Unix, or the time of creation on Windows). """ # FIXME: Return metadata that isn't completely fabricated. return (self.get_mode(), self.inode, MagicDevNumber, self.get_linkcount(), os.getuid(), os.getgid(), self.get_size(), 0, 0, 0) def get_metadata(self): f = self.open('?t=json') json = f.read() f.close() return simplejson.loads(json) def open(self, postfix=''): url = self.fullurl + postfix print '*** Fetching:', `url` return urllib.urlopen(url) class TahoeFile (TahoeNode): def __init__(self, baseurl, uri): assert uri.split(':', 2)[1] in ('CHK', 'LIT'), `uri` TahoeNode.__init__(self, baseurl, uri) # nonfuse: def get_mode(self): return stat.S_IFREG | 0400 # Read only regular file. def get_linkcount(self): return 1 def get_size(self): return self.get_metadata()[1]['size'] def resolve_path(self, path): assert type(path) is list assert path == [] return self class TahoeDir (TahoeNode): def __init__(self, baseurl, uri): assert uri.split(':', 2)[1] in ('DIR', 'DIR-RO'), `uri` TahoeNode.__init__(self, baseurl, uri) self.mode = stat.S_IFDIR | 0500 # Read only directory. # FUSE: def getdir(self): d = [('.', self.get_mode()), ('..', self.get_mode())] for name, child in self.get_children().items(): if name: # Just ignore this crazy case! d.append((name, child.get_mode())) return d # nonfuse: def get_mode(self): return stat.S_IFDIR | 0500 # Read only directory. def get_linkcount(self): return len(self.getdir()) def get_size(self): return 2 ** 12 # FIXME: What do we return here? len(self.get_metadata()) def resolve_path(self, path): assert type(path) is list if path: head = path[0] child = self.get_child(head) return child.resolve_path(path[1:]) else: return self def get_child(self, name): c = self.get_children() return c[name] def get_children(self): flag, md = self.get_metadata() assert flag == 'dirnode' c = {} for name, (childflag, childmd) in md['children'].items(): if childflag == 'dirnode': cls = TahoeDir else: cls = TahoeFile c[str(name)] = cls(self.burl, childmd['ro_uri']) return c if __name__ == '__main__': main()