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如何在 Linux 下使用 C 获取有关进程状态的信息（即，如果它是僵尸）？

在阅读了到目前为止的答案之后，我想稍微缩小我的问题范围：我更喜欢纯 C 解决方案。在阅读了 ps 源代码（读取 /proc/）后，我认为应该有更好的方法并在这里问:)

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您需要了解如何通过典型的 C 标准库调用与 /proc/“伪文件系统”进行交互。入门所需的文档包含在任何 Linux 发行版中，只需 google 搜索即可。

（现在您知道要搜索什么了。我知道这通常是最大的挑战！）

简而言之，正在运行的 Linux 系统的 /proc/ 目录中的目录和文件反映了正在运行的内核的状态，其中（自然）包括进程。但是，在您收费之前，您需要记住一些信息。

A zombie process isn't the same thing as an orphaned process. An orphaned process is a process left running in a waiting state after the process' parent has exited incorrectly. A zombie process is a process which has exited properly, released all its resources, but is maintaining a place in the process table.

This typically happens when a process is launched by a program. You see, the kernel won't remove a finished sub-process' entry in the process table until the parent program properly fetches the return status of the sub-process. That makes sense; how else would the parent program know if the subprocess exited improperly?

So all subprocesses are technically zombies for at least a very short time. It's not inherently a bad state for a program to be in.

Indeed, "zombies" are sometimes created intentionally. For example, sometimes a zombie entry is left in place by a program for a while so that further launched processes won't get the same PID as the previously-launched (and now zombie) process.

In other words, if you go SIGCHLDing zombie processes unnecessarily you might create a serious problem for the spawning program. However, if a process has been a zombie for a half hour or more, it's probably a sign of a bug.

Edit: The question changed on me! No, there's no simpler way than how ps does it. If there was, it would have been integrated into ps a long time ago. The /proc files are the be-all-end-all source for information on the kernel's state. :)

于 2009-03-11T14:23:36.360 回答
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我只知道两种方法：

  • 解析ps命令的输出
  • 读取 /proc/PID 中的文件，其中 PID 是进程标识符（这就是ps内部执行的操作）
于 2009-03-11T14:02:42.680 回答
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您希望在您的机器上运行的进程然后使用

$ ps辅助

ps显示有关活动进程选择的信息。如果您想要重复更新选择和显示的信息，请改用top。

于 2009-03-11T14:05:18.617 回答
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Pseudo file system /proc is describing kernel internal data structures and gives to you opportunity to alter some values directly. Obtaining state of particular process can be easily implemented with I/O C functions. The right file to parse is: /proc/{PID}/status

Command below can be used to obtain processes in Zombie state.

for proc in $(echo /proc/[0-9]*);do if [[ $(sed -n '/^State:\tZ/p' ${proc}/status 2>/dev/null) ]];then basename $proc;fi;done
于 2012-04-26T05:17:04.053 回答
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在这里找到：

Use this command to display all of your zombie processes:

ps aux | awk '{ print $8 " " $2 }' | grep -w Z

这可以使用 C 轻松解析。

于 2009-03-11T14:04:14.033 回答