// SPDX-License-Identifier: GPL-2.0
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/blkdev.h>
#include "internal.h"

static int devinfo_show(struct seq_file *f, void *v)
{
        int i = *(loff_t *) v;

        if (i < CHRDEV_MAJOR_MAX) {
                if (i == 0)
                        seq_puts(f, "Character devices:\n");
                chrdev_show(f, i);
        }
#ifdef CONFIG_BLOCK
        else {
                i -= CHRDEV_MAJOR_MAX;
                if (i == 0)
                        seq_puts(f, "\nBlock devices:\n");
                blkdev_show(f, i);
        }
#endif
        return 0;
}

static void *devinfo_start(struct seq_file *f, loff_t *pos)
{
        if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
                return pos;
        return NULL;
}

static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
{
        (*pos)++;
        if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
                return NULL;
        return pos;
}

static void devinfo_stop(struct seq_file *f, void *v)
{
        /* Nothing to do */
}

static const struct seq_operations devinfo_ops = {
        .start = devinfo_start,
        .next  = devinfo_next,
        .stop  = devinfo_stop,
        .show  = devinfo_show
};

static int __init proc_devices_init(void)
{
        struct proc_dir_entry *pde;

        pde = proc_create_seq("devices", 0, NULL, &devinfo_ops);
        pde_make_permanent(pde);
        return 0;
}
fs_initcall(proc_devices_init);