Add base template from Loopback FS from FUSE examples

stagfs.py

+#!/usr/bin/env python
+from __future__ import print_function, absolute_import, division
+
+import logging
+import os
+
+from errno import EACCES
+from os.path import realpath
+from threading import Lock
+
+from fusepy import FUSE, FuseOSError, Operations, LoggingMixIn
+
+
+class Loopback(LoggingMixIn, Operations):
+    def __init__(self, root):
+        self.root = realpath(root)
+        self.rwlock = Lock()
+
+    #def __call__(self, op, path, *args):
+    #    return super(Loopback, self).__call__(op, self.root + path, *args)
+
+    def access(self, path, mode):
+        if not os.access(path, mode):
+            raise FuseOSError(EACCES)
+
+    chmod = os.chmod
+    chown = os.chown
+
+    def create(self, path, mode):
+        return os.open(path, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, mode)
+
+    def flush(self, path, fh):
+        return os.fsync(fh)
+
+    def fsync(self, path, datasync, fh):
+        if datasync != 0:
+            return os.fdatasync(fh)
+        else:
+            return os.fsync(fh)
+
+    def getattr(self, path, fh=None):
+        st = os.lstat(path)
+        return dict((key, getattr(st, key)) for key in (
+            'st_atime', 'st_ctime', 'st_gid', 'st_mode', 'st_mtime',
+            'st_nlink', 'st_size', 'st_uid'))
+
+    getxattr = None
+
+    def link(self, target, source):
+        return os.link(self.root + source, target)
+
+    listxattr = None
+    mkdir = os.mkdir
+    mknod = os.mknod
+    open = os.open
+
+    def read(self, path, size, offset, fh):
+        with self.rwlock:
+            os.lseek(fh, offset, 0)
+            return os.read(fh, size)
+
+    def readdir(self, path, fh):
+        return ['.', '..'] + os.listdir(path)
+
+    readlink = os.readlink
+
+    def release(self, path, fh):
+        return os.close(fh)
+
+    def rename(self, old, new):
+        return os.rename(old, self.root + new)
+
+    rmdir = os.rmdir
+
+    def statfs(self, path):
+        stv = os.statvfs(path)
+        return dict((key, getattr(stv, key)) for key in (
+            'f_bavail', 'f_bfree', 'f_blocks', 'f_bsize', 'f_favail',
+            'f_ffree', 'f_files', 'f_flag', 'f_frsize', 'f_namemax'))
+
+    def symlink(self, target, source):
+        return os.symlink(source, target)
+
+    def truncate(self, path, length, fh=None):
+        with open(path, 'r+') as f:
+            f.truncate(length)
+
+    unlink = os.unlink
+    utimens = os.utime
+
+    def write(self, path, data, offset, fh):
+        with self.rwlock:
+            os.lseek(fh, offset, 0)
+            return os.write(fh, data)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('root')
+    parser.add_argument('mount')
+    args = parser.parse_args()
+
+    logging.basicConfig(level=logging.DEBUG)
+    fuse = FUSE(
+        Loopback(args.root), args.mount, foreground=True, allow_other=True)