seq_file用法

#include <linux/module.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/fs.h>

#define PROC_NAME "myproc"

static int proc_open(struct inode *inodp, struct file *filp);

static struct file_operations proc_fops = {
        .owner = THIS_MODULE,
        .open = proc_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = seq_release,
};

void * seq_start(struct seq_file *m, loff_t *pos)
{
        loff_t *item;

        item = kmalloc(sizeof(loff_t), GFP_KERNEL);
        if (!item)
                goto err;

        *item = *pos;
err:
        return item;
}

void seq_stop(struct seq_file *m, void *v)
{
        kfree(v);
}

void * seq_next(struct seq_file *m, void *v, loff_t *pos)
{
        loff_t *item = (loff_t *) v;

        *pos = ++(*item);

        return item;
}

int seq_show(struct seq_file *m, void *v)
{
        loff_t *item = (loff_t *) v;

        seq_printf(m, "%Ld\n", *item);

        return 0;
}

static struct seq_operations seq_ops = {
        .start = seq_start,
        .stop = seq_stop,
        .next = seq_next,
        .show = seq_show,
};

static int proc_open(struct inode *inodp, struct file *filp)
{
        return seq_open(filp, &seq_ops);
}

static int __init proc_init(void)
{
        struct proc_dir_entry *entry;

        entry = create_proc_entry(PROC_NAME, 0, NULL);
        if (!entry)
                printk(KERN_ALERT "create failure.\n");

        entry->proc_fops = &proc_fops;

        return 0;
}

static void __exit proc_exit(void)
{
        remove_proc_entry(PROC_NAME, NULL);
}

MODULE_LICENSE("GPL");

module_init(proc_init);
module_exit(proc_exit);