自定义linux内核系统调用包装函数

i am writing a custom system call for linux kernel everything works fine with the function call and now i am trying to create a wrapper function in order to use the function normally in any program without using the syscall (call)

我正在为linux内核编写自定义系统调用一切正常,函数调用现在我正在尝试创建一个包装函数,以便在任何程序中正常使用该函数而不使用syscall(调用)

what i have done so far is

到目前为止我所做的是

#include <stdlib.h>
#include<stdio.h>
#include<linux/unistd.h>
#include<errno.h>
#include <sys/types.h>
#include <unistd.h>
#include<string.h>
#include <linux/sched.h>
#include <linux/kernel.h>

long *__wrap_process_info(int myid , void *udata)
{
    return syscall(337 , myid , udata);
}

my system call returns -1 on error and 0 if executed correctly my question is , how to make the wrapper function return the syscall return value ? and ,do i need to include a main in the wrapper function ?

我的系统调用在错误时返回-1,如果正确执行则返回0我的问题是,如何使包装函数返回syscall返回值?而且,我需要在包装函数中包含一个main吗?

1 个解决方案

#1

Assuming that you are using the * as a wildcard and not pointer notation. Your implementation is already returning the value returned by the function syscall. In case there is an error, it's code is stored in errno variable, which you might want to copy to some additional parameter you will pass to your function:

假设您使用*作为通配符而不是指针表示法。您的实现已经返回函数syscall返回的值。如果出现错误,它的代码存储在errno变量中,您可能希望将其复制到您将传递给函数的其他参数:

long <???>__wrap_process_info(int myid , void *udata, long *err )
{
    long result;
    result = syscall(337 , myid , udata);
    *err = errno;
    return result;
}