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 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         int boot_int;
  48
  49         unsigned int uint_0001;
  50
  51         char string_0001[65];
  52
  53 #define SYSCTL_TEST_BITMAP_SIZE 65536
  54         unsigned long *bitmap_0001;
  55 };
  56
  57 static struct test_sysctl_data test_data = {
  58         .int_0001 = 60,
  59         .int_0002 = 1,
  60
  61         .int_0003[0] = 0,
  62         .int_0003[1] = 1,
  63         .int_0003[2] = 2,
  64         .int_0003[3] = 3,
  65
  66         .boot_int = 0,
  67
  68         .uint_0001 = 314,
  69
  70         .string_0001 = "(none)",
  71 };
  72
  73 /* These are all under /proc/sys/debug/test_sysctl/ */
  74 static struct ctl_table test_table[] = {
  75         {
  76                 .procname       = "int_0001",
  77                 .data           = &test_data.int_0001,
  78                 .maxlen         = sizeof(int),
  79                 .mode           = 0644,
  80                 .proc_handler   = proc_dointvec_minmax,
  81                 .extra1         = &i_zero,
  82                 .extra2         = &i_one_hundred,
  83         },
  84         {
  85                 .procname       = "int_0002",
  86                 .data           = &test_data.int_0002,
  87                 .maxlen         = sizeof(int),
  88                 .mode           = 0644,
  89                 .proc_handler   = proc_dointvec,
  90         },
  91         {
  92                 .procname       = "int_0003",
  93                 .data           = &test_data.int_0003,
  94                 .maxlen         = sizeof(test_data.int_0003),
  95                 .mode           = 0644,
  96                 .proc_handler   = proc_dointvec,
  97         },
  98         {
  99                 .procname       = "boot_int",
 100                 .data           = &test_data.boot_int,
 101                 .maxlen         = sizeof(test_data.boot_int),
 102                 .mode           = 0644,
 103                 .proc_handler   = proc_dointvec,
 104                 .extra1         = SYSCTL_ZERO,
 105                 .extra2         = SYSCTL_ONE,
 106         },
 107         {
 108                 .procname       = "uint_0001",
 109                 .data           = &test_data.uint_0001,
 110                 .maxlen         = sizeof(unsigned int),
 111                 .mode           = 0644,
 112                 .proc_handler   = proc_douintvec,
 113         },
 114         {
 115                 .procname       = "string_0001",
 116                 .data           = &test_data.string_0001,
 117                 .maxlen         = sizeof(test_data.string_0001),
 118                 .mode           = 0644,
 119                 .proc_handler   = proc_dostring,
 120         },
 121         {
 122                 .procname       = "bitmap_0001",
 123                 .data           = &test_data.bitmap_0001,
 124                 .maxlen         = SYSCTL_TEST_BITMAP_SIZE,
 125                 .mode           = 0644,
 126                 .proc_handler   = proc_do_large_bitmap,
 127         },
 128         { }
 129 };
 130
 131 static struct ctl_table test_sysctl_table[] = {
 132         {
 133                 .procname       = "test_sysctl",
 134                 .maxlen         = 0,
 135                 .mode           = 0555,
 136                 .child          = test_table,
 137         },
 138         { }
 139 };
 140
 141 static struct ctl_table test_sysctl_root_table[] = {
 142         {
 143                 .procname       = "debug",
 144                 .maxlen         = 0,
 145                 .mode           = 0555,
 146                 .child          = test_sysctl_table,
 147         },
 148         { }
 149 };
 150
 151 static struct ctl_table_header *test_sysctl_header;
 152
 153 static int __init test_sysctl_init(void)
 154 {
 155         test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
 156         if (!test_data.bitmap_0001)
 157                 return -ENOMEM;
 158         test_sysctl_header = register_sysctl_table(test_sysctl_root_table);
 159         if (!test_sysctl_header) {
 160                 kfree(test_data.bitmap_0001);
 161                 return -ENOMEM;
 162         }
 163         return 0;
 164 }
 165 module_init(test_sysctl_init);
 166
 167 static void __exit test_sysctl_exit(void)
 168 {
 169         kfree(test_data.bitmap_0001);
 170         if (test_sysctl_header)
 171                 unregister_sysctl_table(test_sysctl_header);
 172 }
 173
 174 module_exit(test_sysctl_exit);
 175
 176 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
 177 MODULE_LICENSE("GPL");