Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
7static int devinfo_show(struct seq_file *f, void *v)
8{
9 int i = *(loff_t *) v;
10
11 if (i < CHRDEV_MAJOR_MAX) {
12 if (i == 0)
13 seq_puts(f, "Character devices:\n");
14 chrdev_show(f, i);
15 }
16#ifdef CONFIG_BLOCK
17 else {
18 i -= CHRDEV_MAJOR_MAX;
19 if (i == 0)
20 seq_puts(f, "\nBlock devices:\n");
21 blkdev_show(f, i);
22 }
23#endif
24 return 0;
25}
26
27static void *devinfo_start(struct seq_file *f, loff_t *pos)
28{
29 if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
30 return pos;
31 return NULL;
32}
33
34static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
35{
36 (*pos)++;
37 if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
38 return NULL;
39 return pos;
40}
41
42static void devinfo_stop(struct seq_file *f, void *v)
43{
44 /* Nothing to do */
45}
46
47static const struct seq_operations devinfo_ops = {
48 .start = devinfo_start,
49 .next = devinfo_next,
50 .stop = devinfo_stop,
51 .show = devinfo_show
52};
53
54static int devinfo_open(struct inode *inode, struct file *filp)
55{
56 return seq_open(filp, &devinfo_ops);
57}
58
59static const struct file_operations proc_devinfo_operations = {
60 .open = devinfo_open,
61 .read = seq_read,
62 .llseek = seq_lseek,
63 .release = seq_release,
64};
65
66static int __init proc_devices_init(void)
67{
68 proc_create("devices", 0, NULL, &proc_devinfo_operations);
69 return 0;
70}
71fs_initcall(proc_devices_init);