lib/test_sysctl.c

   1 /*
   2  * proc sysctl test driver
   3  *
   4  * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or at your option any
   9  * later version; or, when distributed separately from the Linux kernel or
  10  * when incorporated into other software packages, subject to the following
  11  * license:
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of copyleft-next (version 0.3.1 or later) as published
  15  * at http://copyleft-next.org/.
  16  */
  17
  18 /*
  19  * This module provides an interface to the the proc sysctl interfaces.  This
  20  * driver requires CONFIG_PROC_SYSCTL. It will not normally be loaded by the
  21  * system unless explicitly requested by name. You can also build this driver
  22  * into your kernel.
  23  */
  24
  25 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  26
  27 #include <linux/init.h>
  28 #include <linux/list.h>
  29 #include <linux/module.h>
  30 #include <linux/printk.h>
  31 #include <linux/fs.h>
  32 #include <linux/miscdevice.h>
  33 #include <linux/slab.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/async.h>
  36 #include <linux/delay.h>
  37 #include <linux/vmalloc.h>
  38
  39 static int i_zero;
  40 static int i_one_hundred = 100;
  41
  42 struct test_sysctl_data {
  43         int int_0001;
  44         int int_0002;
  45         int int_0003[4];
  46
  47         unsigned int uint_0001;
  48
  49         char string_0001[65];
  50 };
  51
  52 static struct test_sysctl_data test_data = {
  53         .int_0001 = 60,
  54         .int_0002 = 1,
  55
  56         .int_0003[0] = 0,
  57         .int_0003[1] = 1,
  58         .int_0003[2] = 2,
  59         .int_0003[3] = 3,
  60
  61         .uint_0001 = 314,
  62
  63         .string_0001 = "(none)",
  64 };
  65
  66 /* These are all under /proc/sys/debug/test_sysctl/ */
  67 static struct ctl_table test_table[] = {
  68         {
  69                 .procname       = "int_0001",
  70                 .data           = &test_data.int_0001,
  71                 .maxlen         = sizeof(int),
  72                 .mode           = 0644,
  73                 .proc_handler   = proc_dointvec_minmax,
  74                 .extra1         = &i_zero,
  75                 .extra2         = &i_one_hundred,
  76         },
  77         {
  78                 .procname       = "int_0002",
  79                 .data           = &test_data.int_0002,
  80                 .maxlen         = sizeof(int),
  81                 .mode           = 0644,
  82                 .proc_handler   = proc_dointvec,
  83         },
  84         {
  85                 .procname       = "int_0003",
  86                 .data           = &test_data.int_0003,
  87                 .maxlen         = sizeof(test_data.int_0003),
  88                 .mode           = 0644,
  89                 .proc_handler   = proc_dointvec,
  90         },
  91         {
  92                 .procname       = "uint_0001",
  93                 .data           = &test_data.uint_0001,
  94                 .maxlen         = sizeof(unsigned int),
  95                 .mode           = 0644,
  96                 .proc_handler   = proc_douintvec,
  97         },
  98         {
  99                 .procname       = "string_0001",
 100                 .data           = &test_data.string_0001,
 101                 .maxlen         = sizeof(test_data.string_0001),
 102                 .mode           = 0644,
 103                 .proc_handler   = proc_dostring,
 104         },
 105         { }
 106 };
 107
 108 static struct ctl_table test_sysctl_table[] = {
 109         {
 110                 .procname       = "test_sysctl",
 111                 .maxlen         = 0,
 112                 .mode           = 0555,
 113                 .child          = test_table,
 114         },
 115         { }
 116 };
 117
 118 static struct ctl_table test_sysctl_root_table[] = {
 119         {
 120                 .procname       = "debug",
 121                 .maxlen         = 0,
 122                 .mode           = 0555,
 123                 .child          = test_sysctl_table,
 124         },
 125         { }
 126 };
 127
 128 static struct ctl_table_header *test_sysctl_header;
 129
 130 static int __init test_sysctl_init(void)
 131 {
 132         test_sysctl_header = register_sysctl_table(test_sysctl_root_table);
 133         if (!test_sysctl_header)
 134                 return -ENOMEM;
 135         return 0;
 136 }
 137 late_initcall(test_sysctl_init);
 138
 139 static void __exit test_sysctl_exit(void)
 140 {
 141         if (test_sysctl_header)
 142                 unregister_sysctl_table(test_sysctl_header);
 143 }
 144
 145 module_exit(test_sysctl_exit);
 146
 147 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
 148 MODULE_LICENSE("GPL");