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
devinfo_show(struct seq_file * f,void * v)7 static 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
devinfo_start(struct seq_file * f,loff_t * pos)27 static 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
devinfo_next(struct seq_file * f,void * v,loff_t * pos)34 static 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
devinfo_stop(struct seq_file * f,void * v)42 static void devinfo_stop(struct seq_file *f, void *v)
43 {
44 /* Nothing to do */
45 }
46
47 static const struct seq_operations devinfo_ops = {
48 .start = devinfo_start,
49 .next = devinfo_next,
50 .stop = devinfo_stop,
51 .show = devinfo_show
52 };
53
proc_devices_init(void)54 static int __init proc_devices_init(void)
55 {
56 proc_create_seq("devices", 0, NULL, &devinfo_ops);
57 return 0;
58 }
59 fs_initcall(proc_devices_init);
60