在内核态创建目录

mkdir_kernel.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/namei.h>


static int my_mkdir(const char *name, umode_t mode)
{
    struct dentry *dentry;
    struct path path;
    int error;
    unsigned int lookup_flags = LOOKUP_DIRECTORY;

retry:
    dentry = kern_path_create(AT_FDCWD, name, &path, lookup_flags);
    if (IS_ERR(dentry)) {
        return PTR_ERR(dentry);
    }

    if (!IS_POSIXACL(path.dentry->d_inode))
        mode &= ~current_umask();

    error = security_path_mkdir(&path, dentry, mode);
    if (!error) {
        error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
    }

    done_path_create(&path, dentry);
    if (retry_estale(error, lookup_flags)) {
        lookup_flags |= LOOKUP_REVAL;
        goto retry;
    }

    return error;
}

static int hello_init(void)
{
    int ret;
    printk(KERN_INFO "create a usr directory in kernel.\n");
    ret = my_mkdir("/root/abc", S_IRUGO | S_IWUSR);
    if (ret)
        printk(KERN_ERR "Failed to create directory, errno[%d]\n", ret);
    return ret;
}


static void hello_exit(void)
{
    printk(KERN_INFO "Byebye\n");
}


module_init(hello_init);
module_exit(hello_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Cosysn");
MODULE_DESCRIPTION("This is a demo!\n");

后面可以研究一下如何在内核中删除目录、创建文件、读文件、写文件、删除文件等操作。