_psbsd.py 文件源码

def cwd(self):
        """Return process current working directory."""
        # sometimes we get an empty string, in which case we turn
        # it into None
        if OPENBSD and self.pid == 0:
            return None  # ...else it would raise EINVAL
        elif NETBSD:
            with wrap_exceptions_procfs(self):
                return os.readlink("/proc/%s/cwd" % self.pid)
        elif hasattr(cext, 'proc_open_files'):
            # FreeBSD < 8 does not support functions based on
            # kinfo_getfile() and kinfo_getvmmap()
            return cext.proc_cwd(self.pid) or None
        else:
            raise NotImplementedError(
                "supported only starting from FreeBSD 8" if
                FREEBSD else "")