1 #include <linux/fs.h>
2 #include <linux/init.h>
3 #include <linux/proc_fs.h>
4 #include <linux/seq_file.h>
5
devinfo_show(struct seq_file * f,void * v)6 static int devinfo_show(struct seq_file *f, void *v)
7 {
8 int i = *(loff_t *) v;
9
10 if (i < CHRDEV_MAJOR_HASH_SIZE) {
11 if (i == 0)
12 seq_puts(f, "Character devices:\n");
13 chrdev_show(f, i);
14 }
15 #ifdef CONFIG_BLOCK
16 else {
17 i -= CHRDEV_MAJOR_HASH_SIZE;
18 if (i == 0)
19 seq_puts(f, "\nBlock devices:\n");
20 blkdev_show(f, i);
21 }
22 #endif
23 return 0;
24 }
25
devinfo_start(struct seq_file * f,loff_t * pos)26 static void *devinfo_start(struct seq_file *f, loff_t *pos)
27 {
28 if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
29 return pos;
30 return NULL;
31 }
32
devinfo_next(struct seq_file * f,void * v,loff_t * pos)33 static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
34 {
35 (*pos)++;
36 if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
37 return NULL;
38 return pos;
39 }
40
devinfo_stop(struct seq_file * f,void * v)41 static void devinfo_stop(struct seq_file *f, void *v)
42 {
43 /* Nothing to do */
44 }
45
46 static const struct seq_operations devinfo_ops = {
47 .start = devinfo_start,
48 .next = devinfo_next,
49 .stop = devinfo_stop,
50 .show = devinfo_show
51 };
52
devinfo_open(struct inode * inode,struct file * filp)53 static int devinfo_open(struct inode *inode, struct file *filp)
54 {
55 return seq_open(filp, &devinfo_ops);
56 }
57
58 static const struct file_operations proc_devinfo_operations = {
59 .open = devinfo_open,
60 .read = seq_read,
61 .llseek = seq_lseek,
62 .release = seq_release,
63 };
64
proc_devices_init(void)65 static int __init proc_devices_init(void)
66 {
67 proc_create("devices", 0, NULL, &proc_devinfo_operations);
68 return 0;
69 }
70 module_init(proc_devices_init);
71