fs/lockd/procfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Procfs support for lockd
   4  *
   5  * Copyright (c) 2014 Jeff Layton <jlayton@primarydata.com>
   6  */
   7
   8 #include <linux/fs.h>
   9 #include <linux/proc_fs.h>
  10 #include <linux/module.h>
  11 #include <linux/nsproxy.h>
  12 #include <net/net_namespace.h>
  13
  14 #include "netns.h"
  15 #include "procfs.h"
  16
  17 /*
  18  * We only allow strings that start with 'Y', 'y', or '1'.
  19  */
  20 static ssize_t
  21 nlm_end_grace_write(struct file *file, const char __user *buf, size_t size,
  22                     loff_t *pos)
  23 {
  24         char *data;
  25         struct lockd_net *ln = net_generic(current->nsproxy->net_ns,
  26                                            lockd_net_id);
  27
  28         if (size < 1)
  29                 return -EINVAL;
  30
  31         data = simple_transaction_get(file, buf, size);
  32         if (IS_ERR(data))
  33                 return PTR_ERR(data);
  34
  35         switch(data[0]) {
  36         case 'Y':
  37         case 'y':
  38         case '1':
  39                 locks_end_grace(&ln->lockd_manager);
  40                 break;
  41         default:
  42                 return -EINVAL;
  43         }
  44
  45         return size;
  46 }
  47
  48 static ssize_t
  49 nlm_end_grace_read(struct file *file, char __user *buf, size_t size,
  50                    loff_t *pos)
  51 {
  52         struct lockd_net *ln = net_generic(current->nsproxy->net_ns,
  53                                            lockd_net_id);
  54         char resp[3];
  55
  56         resp[0] = list_empty(&ln->lockd_manager.list) ? 'Y' : 'N';
  57         resp[1] = '\n';
  58         resp[2] = '\0';
  59
  60         return simple_read_from_buffer(buf, size, pos, resp, sizeof(resp));
  61 }
  62
  63 static const struct file_operations lockd_end_grace_operations = {
  64         .write          = nlm_end_grace_write,
  65         .read           = nlm_end_grace_read,
  66         .llseek         = default_llseek,
  67         .release        = simple_transaction_release,
  68 };
  69
  70 int __init
  71 lockd_create_procfs(void)
  72 {
  73         struct proc_dir_entry *entry;
  74
  75         entry = proc_mkdir("fs/lockd", NULL);
  76         if (!entry)
  77                 return -ENOMEM;
  78         entry = proc_create("nlm_end_grace", S_IRUGO|S_IWUSR, entry,
  79                                  &lockd_end_grace_operations);
  80         if (!entry) {
  81                 remove_proc_entry("fs/lockd", NULL);
  82                 return -ENOMEM;
  83         }
  84         return 0;
  85 }
  86
  87 void __exit
  88 lockd_remove_procfs(void)
  89 {
  90         remove_proc_entry("fs/lockd/nlm_end_grace", NULL);
  91         remove_proc_entry("fs/lockd", NULL);
  92 }