subprocess.py 文件源码

def _close_fds(self, keep):
            # `keep` is a set of fds, so we
            # use os.closerange from 3 to min(keep)
            # and then from max(keep + 1) to MAXFD and
            # loop through filling in the gaps.
            # Under new python versions, we need to explicitly set
            # passed fds to be inheritable or they will go away on exec
            if hasattr(os, 'set_inheritable'):
                set_inheritable = os.set_inheritable
            else:
                set_inheritable = lambda i, v: True
            if hasattr(os, 'closerange'):
                keep = sorted(keep)
                min_keep = min(keep)
                max_keep = max(keep)
                os.closerange(3, min_keep)
                os.closerange(max_keep + 1, MAXFD)
                for i in xrange(min_keep, max_keep):
                    if i in keep:
                        set_inheritable(i, True)
                        continue

                    try:
                        os.close(i)
                    except:
                        pass
            else:
                for i in xrange(3, MAXFD):
                    if i in keep:
                        set_inheritable(i, True)
                        continue
                    try:
                        os.close(i)
                    except:
                        pass