如何在epoll_wait之后更新epoll事件？(How to update epoll events after epoll_wait?)

 我有以下代码摘录（经过严格修改以删除不重要的细节），这些代码在罕见且特殊情况下失败。 
 
struct epoll_event *events = calloc(MAXEVENTS+1, sizeof(struct epoll_event));
struct sockaddr_in in_addr;
socklen_t in_len = sizeof in_addr;

while(1)
  {
  int n = epoll_wait(efd,events, MAXEVENTS, -1);
  for(int i=0; i<n; i++)
    {
    struct epoll_event *evI = &events[i];
    uint64 u64 = evI->data.u64;
    int type = u64>>32, fd=u64, fdx = fd;

    if(type == -1)
      {
      while((fd = accept4(fdx, &in_addr, &in_len, SOCK_NONBLOCK|SOCK_CLOEXEC))>-1)
        {
        setNew_Connection(efd, fd);
        storeAddrPort(fd, &in_addr, &in_len);
        }
      }
    else
      {
      if(evI->events&(EPOLLERR|EPOLLHUP|EPOLLRDHUP)){closeConnection(fd);}
      if(evI->events&EPOLLOUT)  //process out data stuff
      else if(evI->events&EPOLLIN) //process in data stuff and possibly close a different connection.
      }
    }
  }
 
 侦听套接字在evI->data.u64的上半部分用-1来evI->data.u64 
 
 setNew_Connection通常接受像添加epoll等新套接字的东西 
 
 EPOLLET 。 
 
 现在一切都运行得非常好，除非在以下情况下它失败，因为events只在epoll_wait更新，所以连接闭包不会影响n事件，直到返回到while(1)循环的顶部。 
 
 
 
 epoll_wait用在事件结构表中排队的3个事件epoll_wait 。 
 
 
 第一个事件（n = 0）是在代码决定关闭连接（例如文件描述符8）之后的传入数据，因为它不再需要。 
 
 
 第二个事件（n = 1）是传入的新连接。 accept4指定最近可用的fd：8。 setNew_Connection将其添加到epoll列表中。 
 
 
 第三个事件是在步骤2中关闭的连接的输入数据，即fd：8，但由于原始fd：8连接已关闭且当前fd：8用于不同连接，因此它不再有效。 
 
 
 我希望我已经充分解释了这个问题。 问题是，在关闭连接之前， events表中的排队事件不会更新，直到代码返回到epoll_wait 。 我怎么能解决这个问题呢？ 

I have the following code excerpt (heavily redacted to remove unimportant details) which fails under a rare and particular set of circumstances.
 
struct epoll_event *events = calloc(MAXEVENTS+1, sizeof(struct epoll_event));
struct sockaddr_in in_addr;
socklen_t in_len = sizeof in_addr;

while(1)
  {
  int n = epoll_wait(efd,events, MAXEVENTS, -1);
  for(int i=0; i<n; i++)
    {
    struct epoll_event *evI = &events[i];
    uint64 u64 = evI->data.u64;
    int type = u64>>32, fd=u64, fdx = fd;

    if(type == -1)
      {
      while((fd = accept4(fdx, &in_addr, &in_len, SOCK_NONBLOCK|SOCK_CLOEXEC))>-1)
        {
        setNew_Connection(efd, fd);
        storeAddrPort(fd, &in_addr, &in_len);
        }
      }
    else
      {
      if(evI->events&(EPOLLERR|EPOLLHUP|EPOLLRDHUP)){closeConnection(fd);}
      if(evI->events&EPOLLOUT)  //process out data stuff
      else if(evI->events&EPOLLIN) //process in data stuff and possibly close a different connection.
      }
    }
  }
 
Listening sockets are differentiated by -1 in the upper part of evI->data.u64
 
setNew_Connection does the usual accepting stuff like adding the new socket to epoll etc
 
EPOLLET is used.
 
Now it all works brilliantly except under the following circumstances it fails because events is only updated in the epoll_wait so a connection closure does not affect the n events until after returning to the top of the while(1) loop.
 
 
 
epoll_wait unblocks with 3 events queued in the events struct table.
 
 
First event (n=0), is incoming data after which code decides to close a connection (e.g. file descriptor 8) as it is no longer needed.
 
 
2nd event (n=1) is an incoming new connection. accept4 assigns fd:8 as it has recently become available. setNew_Connection adds it to the epoll list.
 
 
3rd event is incoming data for the connection closed in step 2. i.e. fd:8 but it is no longer valid as the original fd:8 connection was closed and the current fd:8 is for a different connection.
 
 
I hope I have explained the problem adequately. The issue is that queued events in the events table are not updated when a connection is closed until the code returns to epoll_wait. How can I code around this problem?

原文：https://stackoverflow.com/questions/33382000