Make hello example work

eufs/main.py

@@ -1,2 +1,88 @@
+import errno
+import os
+import stat
+
+import fuse
+
+fuse.fuse_python_api = (0, 2)
+
+
+# For debugging
+
+f = open("log.txt", "w")
+
+
+def log(str):
+    f.write(f"{str}\n")
+    f.flush()
+
+
+hello_path = "/hello"
+hello_str = b"Hello World!\n"
+
+
+class MyStat(fuse.Stat):
+    def __init__(self):
+        self.st_mode = 0
+        self.st_ino = 0
+        self.st_dev = 0
+        self.st_nlink = 0
+        self.st_uid = 0
+        self.st_gid = 0
+        self.st_size = 0
+        self.st_atime = 0
+        self.st_mtime = 0
+        self.st_ctime = 0
+
+
+class HelloFS(fuse.Fuse):
+    def getattr(self, path):
+        log(f"getattr: {path!r}")
+        st = MyStat()
+        if path == "/":
+            st.st_mode = stat.S_IFDIR | 0o755
+            st.st_nlink = 2
+        elif path == hello_path:
+            st.st_mode = stat.S_IFREG | 0o444
+            st.st_nlink = 1
+            st.st_size = len(hello_str)
+        else:
+            return -errno.ENOENT
+        return st
+
+    def readdir(self, path, offset):
+        log(f"readdir: {path!r} {offset!r}")
+        for r in ".", "..", hello_path[1:]:
+            yield fuse.Direntry(r)
+
+    def open(self, path, flags):
+        log(f"open: {path!r} {flags!r}")
+        if path != hello_path:
+            return -errno.ENOENT
+        accmode = os.O_RDONLY | os.O_WRONLY | os.O_RDWR
+        if (flags & accmode) != os.O_RDONLY:
+            return -errno.EACCES
+
+    def read(self, path, size, offset):
+        log(f"read: {path!r} {size!r} {offset!r}")
+        if path != hello_path:
+            return -errno.ENOENT
+        slen = len(hello_str)
+        if offset < slen:
+            if offset + size > slen:
+                size = slen - offset
+            buf = hello_str[offset : offset + size]
+        else:
+            buf = b""
+        return buf
+
+
 def main():
-    print("Hello world!")
+    server = HelloFS(version="%prog " + fuse.__version__, dash_s_do="setsingle")
+
+    server.parse(errex=1)
+    server.main()
+
+
+if __name__ == "__main__":
+    main()