LXR linux/fs/proc/devices.c

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