1// SPDX-License-Identifier: GPL-2.0
2#include <linux/fs.h>
3#include <linux/init.h>
4#include <linux/proc_fs.h>
5#include <linux/seq_file.h>
6#include <linux/blkdev.h>
7#include "internal.h"
8
9static int devinfo_show(struct seq_file *f, void *v)
10{
11	int i = *(loff_t *) v;
12
13	if (i < CHRDEV_MAJOR_MAX) {
14		if (i == 0)
15			seq_puts(f, "Character devices:\n");
16		chrdev_show(f, i);
17	}
18#ifdef CONFIG_BLOCK
19	else {
20		i -= CHRDEV_MAJOR_MAX;
21		if (i == 0)
22			seq_puts(f, "\nBlock devices:\n");
23		blkdev_show(f, i);
24	}
25#endif
26	return 0;
27}
28
29static void *devinfo_start(struct seq_file *f, loff_t *pos)
30{
31	if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
32		return pos;
33	return NULL;
34}
35
36static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
37{
38	(*pos)++;
39	if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
40		return NULL;
41	return pos;
42}
43
44static void devinfo_stop(struct seq_file *f, void *v)
45{
46	/* Nothing to do */
47}
48
49static const struct seq_operations devinfo_ops = {
50	.start = devinfo_start,
51	.next  = devinfo_next,
52	.stop  = devinfo_stop,
53	.show  = devinfo_show
54};
55
56static int __init proc_devices_init(void)
57{
58	struct proc_dir_entry *pde;
59
60	pde = proc_create_seq("devices", 0, NULL, &devinfo_ops);
61	pde_make_permanent(pde);
62	return 0;
63}
64fs_initcall(proc_devices_init);
65