xref: /openbmc/linux/fs/proc/devices.c (revision 7587cdef)
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  
9  static 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  
29  static 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  
36  static 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  
44  static void devinfo_stop(struct seq_file *f, void *v)
45  {
46  	/* Nothing to do */
47  }
48  
49  static const struct seq_operations devinfo_ops = {
50  	.start = devinfo_start,
51  	.next  = devinfo_next,
52  	.stop  = devinfo_stop,
53  	.show  = devinfo_show
54  };
55  
56  static 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  }
64  fs_initcall(proc_devices_init);
65