在父进程中杀死僵尸子进程

发布于 2024-12-14 15:51:49 字数 401 浏览 0 评论 0原文

所以我想做以下事情：
设置一个派生一堆进程的守护进程。

所以守护进程分叉了一堆进程然后分叉另一组进程，

问题是子进程可能需要很长时间才能退出。如果父进程尽管分叉子进程还有其他工作要做，如何防止僵尸子进程？

父进程（守护进程）执行类似以下操作：

while(true)
{
SQL QUERY EXECUTED

   while(mysql_fetch_array)
   {
       Fork children
   }
}

问题是，如果父进程除了分叉子进程之外还必须执行其他工作，并且子进程需要很长时间才能退出，那么我如何等待子进程退出。

我使用系统守护程序 PEAR 函数来创建守护程序，并使用 pcntl_fork 函数来创建进程。

原文

So I want to do the following:
Set up a daemon that forks a bunch of processes.

So the Daemon forks a bunch of processes
then forks another bunch of processes

the problem is the child processes might take a long time to exit. How do I prevent zombie children if the parent process has other work to do despite forking children?

The parent process (the daemon) does something like this:

while(true)
{
SQL QUERY EXECUTED

   while(mysql_fetch_array)
   {
       Fork children
   }
}

The problem is how can I wait for the children processes to exit if the parent process has to do other work besides forking children and if the children take a long time to exit.

I am using the System daemon PEAR function to create the daemon and the pcntl_fork function to create the processes.

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凉城已无爱 2024-12-21 15:51:49

我不记得我在哪里看到过这个：

Parent forks child
  Waits until child is dead  (this won't take long, see ahead)
  Goes on

Child does only 2 things:
  Forks a grandchild
  Exits

Grandchild does whatever work is needed
  Exits

诀窍是，当孙子去世时，它的父母（你的孩子之一）已经死了。但必须通知有人死亡。看起来，在 Linux 系统中，收到通知的不是祖父母，而是所有的祖父母。因为该进程知道自己的工作，所以它会定期检查死去的孩子，并不允许他们成为僵尸。

这是一个带有解释的链接： http://fixunix.com/unix/533215 -how-avoid-zombie-processes.html

当一个进程的父进程终止时，“init”进程将接管它的进程
父母。所以当子进程退出时，孙进程就失去了它的
父级，并被 init采用。 Init 总是收获它死去的孩子，所以
他们不会变成僵尸。

I don't remember where I saw this:

Parent forks child
  Waits until child is dead  (this won't take long, see ahead)
  Goes on

Child does only 2 things:
  Forks a grandchild
  Exits

Grandchild does whatever work is needed
  Exits

The trick is that when the Granchild dies, its parent (one of your Children) is already dead. But someone has to be notified for the death. It appears that in Linux systems, it's not the grandparent that is notified but the grand-grand-...-grandparent of all. And because that process knows its job, it periodically checks for dead children and does not allow them to become zombies.

Here's a link with explanation: http://fixunix.com/unix/533215-how-avoid-zombie-processes.html

When a process's parent terminates, the "init" process takes over as its
parent. So when the child process exits, the grandchild loses its
parent, and is adopted by init. Init always reaps its dead children, so
they don't become zombies.

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