在内核模块中创建到文件的符号链接

Question

I am trying to create a symbolic link to a file in a Linux kernel module. With the following code, I have created a directory in sys/kernel and then created a file in that directory:

// Create the base directory in sys/kernel
    if (!(pmd_kobjSysKernelDir =
            kobject_create_and_add(PMD_DRIVER_NAME, kernel_kobj)))
        return -ENODEV;

    if ((retVal = sysfs_create_file(
            pmd_kobjSysKernelDir, &dev_attr_sysfs.attr)))
    {
        dev_err(&client->dev,
                "couldn't create %s file \n", dev_attr_sysfs.attr.name);
        return retVal;
    }

Now I am trying to create a symbolic link to the file, that is represented by the dev_attr_sysfs structure. The problem is, I only found sysfs_create_link function, which seems to be able to create only directory symbolic links (I think). Is there a way to use it in order to create a symbolic link to a file? If not, is there any other dedicated function?

Answer 1

You can directly call sys_symlink or sys_symlinkat . Or it is better to look in implementation file fs/namei.c .