如何在Linux的内核空间中使用ioctl()? [英] How to use ioctl() from kernel space in Linux?

问题描述

是否可以从Linux内核模块调用ioctl? 谁能提供一个使用示例?

Is it possible to call ioctl from a Linux kernel module? Can anyone provide an example of how it's used?

推荐答案

您可以尝试致电sys_ioctl.
如果内核是使用CONFIG_COMPAT编译的，则将其导出.

You can try to call sys_ioctl.
It's exported if the kernel is compiled with CONFIG_COMPAT.

或者，如果您拥有设备驱动程序的struct file_operations，则可以直接调用其ioctl处理程序.

Or, if you have the device driver's struct file_operations, you can call its ioctl handler directly.

但是，ioctl句柄希望指针参数位于当前正在运行的进程的地址空间中，而不是内核地址空间中. copy_from_user将用于读取它们.如果您提供指向内核地址空间的指针，则copy_from_user将失败.我看不出你将如何解决这个问题.

However, the ioctl handle would expect pointer parameters to be in the address space of the process currently running, not in the kernel address space. copy_from_user would be used to read them. If you give pointers to the kernel address space, copy_from_user will fail. I don't see how you would get around this.

如果您要在以下代码之间调用ioctl处理程序，则copy_from_user永远不会失败.

If you will call ioctl handler between below code than copy_from_user will not ever fail.

 mm_segment_t fs;

  fs = get_fs();     /* save previous value */
  set_fs (get_ds()); /* use kernel limit */

  /* system calls can be invoked */

  set_fs(fs); /* restore before returning to user space */

这篇关于如何在Linux的内核空间中使用ioctl()?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！