Linux下的TFTP源代码

				/*				 * dup2.c				 *				 * Ersatz dup2() for really ancient systems				 */								#include "config.h"								int dup2(int oldfd, int newfd)				{				  int rv, nfd;								  close(newfd);								  nfd = rv = dup(oldfd);								  if (rv >= 0 && rv != newfd) {				    rv = dup2(oldfd, newfd);				    close(nfd);				  }								  return rv;				}