lib/test_sysctl.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1
   2 /*
   3  * proc sysctl test driver
   4  *
   5  * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org>
   6  */
   7
   8 /*
   9  * This module provides an interface to the proc sysctl interfaces.  This
  10  * driver requires CONFIG_PROC_SYSCTL. It will not normally be loaded by the
  11  * system unless explicitly requested by name. You can also build this driver
  12  * into your kernel.
  13  */
  14
  15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/init.h>
  18 #include <linux/list.h>
  19 #include <linux/module.h>
  20 #include <linux/printk.h>
  21 #include <linux/fs.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/slab.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/async.h>
  26 #include <linux/delay.h>
  27 #include <linux/vmalloc.h>
  28
  29 static int i_zero;
  30 static int i_one_hundred = 100;
  31 static int match_int_ok = 1;
  32
  33 struct test_sysctl_data {
  34         int int_0001;
  35         int int_0002;
  36         int int_0003[4];
  37
  38         int boot_int;
  39
  40         unsigned int uint_0001;
  41
  42         char string_0001[65];
  43
  44 #define SYSCTL_TEST_BITMAP_SIZE 65536
  45         unsigned long *bitmap_0001;
  46 };
  47
  48 static struct test_sysctl_data test_data = {
  49         .int_0001 = 60,
  50         .int_0002 = 1,
  51
  52         .int_0003[0] = 0,
  53         .int_0003[1] = 1,
  54         .int_0003[2] = 2,
  55         .int_0003[3] = 3,
  56
  57         .boot_int = 0,
  58
  59         .uint_0001 = 314,
  60
  61         .string_0001 = "(none)",
  62 };
  63
  64 /* These are all under /proc/sys/debug/test_sysctl/ */
  65 static struct ctl_table test_table[] = {
  66         {
  67                 .procname       = "int_0001",
  68                 .data           = &test_data.int_0001,
  69                 .maxlen         = sizeof(int),
  70                 .mode           = 0644,
  71                 .proc_handler   = proc_dointvec_minmax,
  72                 .extra1         = &i_zero,
  73                 .extra2         = &i_one_hundred,
  74         },
  75         {
  76                 .procname       = "int_0002",
  77                 .data           = &test_data.int_0002,
  78                 .maxlen         = sizeof(int),
  79                 .mode           = 0644,
  80                 .proc_handler   = proc_dointvec,
  81         },
  82         {
  83                 .procname       = "int_0003",
  84                 .data           = &test_data.int_0003,
  85                 .maxlen         = sizeof(test_data.int_0003),
  86                 .mode           = 0644,
  87                 .proc_handler   = proc_dointvec,
  88         },
  89         {
  90                 .procname       = "match_int",
  91                 .data           = &match_int_ok,
  92                 .maxlen         = sizeof(match_int_ok),
  93                 .mode           = 0444,
  94                 .proc_handler   = proc_dointvec,
  95         },
  96         {
  97                 .procname       = "boot_int",
  98                 .data           = &test_data.boot_int,
  99                 .maxlen         = sizeof(test_data.boot_int),
 100                 .mode           = 0644,
 101                 .proc_handler   = proc_dointvec,
 102                 .extra1         = SYSCTL_ZERO,
 103                 .extra2         = SYSCTL_ONE,
 104         },
 105         {
 106                 .procname       = "uint_0001",
 107                 .data           = &test_data.uint_0001,
 108                 .maxlen         = sizeof(unsigned int),
 109                 .mode           = 0644,
 110                 .proc_handler   = proc_douintvec,
 111         },
 112         {
 113                 .procname       = "string_0001",
 114                 .data           = &test_data.string_0001,
 115                 .maxlen         = sizeof(test_data.string_0001),
 116                 .mode           = 0644,
 117                 .proc_handler   = proc_dostring,
 118         },
 119         {
 120                 .procname       = "bitmap_0001",
 121                 .data           = &test_data.bitmap_0001,
 122                 .maxlen         = SYSCTL_TEST_BITMAP_SIZE,
 123                 .mode           = 0644,
 124                 .proc_handler   = proc_do_large_bitmap,
 125         },
 126         { }
 127 };
 128
 129 static struct ctl_table_header *test_sysctl_header;
 130
 131 static int __init test_sysctl_init(void)
 132 {
 133         int i;
 134
 135         struct {
 136                 int defined;
 137                 int wanted;
 138         } match_int[] = {
 139                 {.defined = *(int *)SYSCTL_ZERO,        .wanted = 0},
 140                 {.defined = *(int *)SYSCTL_ONE,         .wanted = 1},
 141                 {.defined = *(int *)SYSCTL_TWO,         .wanted = 2},
 142                 {.defined = *(int *)SYSCTL_THREE,       .wanted = 3},
 143                 {.defined = *(int *)SYSCTL_FOUR,        .wanted = 4},
 144                 {.defined = *(int *)SYSCTL_ONE_HUNDRED, .wanted = 100},
 145                 {.defined = *(int *)SYSCTL_TWO_HUNDRED, .wanted = 200},
 146                 {.defined = *(int *)SYSCTL_ONE_THOUSAND, .wanted = 1000},
 147                 {.defined = *(int *)SYSCTL_THREE_THOUSAND, .wanted = 3000},
 148                 {.defined = *(int *)SYSCTL_INT_MAX,     .wanted = INT_MAX},
 149                 {.defined = *(int *)SYSCTL_MAXOLDUID,   .wanted = 65535},
 150                 {.defined = *(int *)SYSCTL_NEG_ONE,     .wanted = -1},
 151         };
 152
 153         for (i = 0; i < ARRAY_SIZE(match_int); i++)
 154                 if (match_int[i].defined != match_int[i].wanted)
 155                         match_int_ok = 0;
 156
 157         test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
 158         if (!test_data.bitmap_0001)
 159                 return -ENOMEM;
 160         test_sysctl_header = register_sysctl("debug/test_sysctl", test_table);
 161         if (!test_sysctl_header) {
 162                 kfree(test_data.bitmap_0001);
 163                 return -ENOMEM;
 164         }
 165         return 0;
 166 }
 167 module_init(test_sysctl_init);
 168
 169 static void __exit test_sysctl_exit(void)
 170 {
 171         kfree(test_data.bitmap_0001);
 172         if (test_sysctl_header)
 173                 unregister_sysctl_table(test_sysctl_header);
 174 }
 175
 176 module_exit(test_sysctl_exit);
 177
 178 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
 179 MODULE_LICENSE("GPL");