int close_pipe(int p[]);
-ssize_t loop_read(int fd, void *buf, size_t nbytes);
+ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll);
+ssize_t loop_write(int fd, const void *buf, size_t nbytes, bool do_poll);
int path_is_mount_point(const char *path);