fs/lockd/procfs.c

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