如何使用来自 Linux 内核模块的 Linux 系统调用 [英] How do I use a Linux System call from a Linux Kernel Module

问题描述

我在从 Linux 内核模块内部调用系统调用时遇到了一些困难.系统调用已经过标准 c 用户空间程序的测试和正常工作，但我似乎无法让内核模块编译和运行它们.

I am having some difficulty calling a system call from inside a Linux Kernel Module. The system calls have been tested and work properly from a standard c user space program but I can't seem to get the kernel module to compile and run them.

在我的用户程序中，我包含以下代码并且系统调用有效:

In my user program I include the following code and the system call works:

#include <linux/unistd.h>   
#define __NR_sys_mycall 343

extern long int _syscall(long int_sysno,...)__THROW;

//and then a simple call is done as such
long value = syscall(__NR_sys_mycall);

printf("The value is %ld
",value);

但是当我在我的 Linux 内核模块中尝试同样的事情时，我得到了一堆错误，要么说错误:函数 'syscall' 的隐式声明(如果我不包括 _syscall 定义)或一长串错误关于语法，如果我这样做...所以我的假设是我需要内核空间版本来调用系统调用.我是对还是错?

But when I try the same thing in my Linux Kernel Module I get a bunch of errors that either say error: implicit declaration of function 'syscall' (if I don't include the _syscall definition) or a long list of errors about syntax if I do...so my assumption is that I need the kernel space version to call the system call. Am I right or wrong?

//My LKM code
#include <linux/module.h>
#include <linux/unistd.h>
#define __NR_sys_mycall 343

static int start_init(void)
{
   long value = syscall(__NR_sys_mycall);
   printk("The value is %ld
",value);

   return 0;
}

static void finish_exit(void)
{
      printk("Done!
");
}

module_init(start_init);
module_exit(finish_exit);

推荐答案

可以直接调用sys_mycall.

#include <linux/module.h>
#include <linux/unistd.h>


static int start_init(void)
{
   long value = sys_mycall (pass_arguments)
   printk("The value is %ld
",value);

   return 0;
}

static void finish_exit(void)
{
      printk("Done!
");
}

module_init(start_init);
module_exit(finish_exit);

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