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
  34 static struct {
  35         struct ctl_table_header *test_h_setup_node;
  36         struct ctl_table_header *test_h_mnt;
  37         struct ctl_table_header *test_h_mnterror;
  38 } sysctl_test_headers;
  39
  40 struct test_sysctl_data {
  41         int int_0001;
  42         int int_0002;
  43         int int_0003[4];
  44
  45         int boot_int;
  46
  47         unsigned int uint_0001;
  48
  49         char string_0001[65];
  50
  51 #define SYSCTL_TEST_BITMAP_SIZE 65536
  52         unsigned long *bitmap_0001;
  53 };
  54
  55 static struct test_sysctl_data test_data = {
  56         .int_0001 = 60,
  57         .int_0002 = 1,
  58
  59         .int_0003[0] = 0,
  60         .int_0003[1] = 1,
  61         .int_0003[2] = 2,
  62         .int_0003[3] = 3,
  63
  64         .boot_int = 0,
  65
  66         .uint_0001 = 314,
  67
  68         .string_0001 = "(none)",
  69 };
  70
  71 /* These are all under /proc/sys/debug/test_sysctl/ */
  72 static struct ctl_table test_table[] = {
  73         {
  74                 .procname       = "int_0001",
  75                 .data           = &test_data.int_0001,
  76                 .maxlen         = sizeof(int),
  77                 .mode           = 0644,
  78                 .proc_handler   = proc_dointvec_minmax,
  79                 .extra1         = &i_zero,
  80                 .extra2         = &i_one_hundred,
  81         },
  82         {
  83                 .procname       = "int_0002",
  84                 .data           = &test_data.int_0002,
  85                 .maxlen         = sizeof(int),
  86                 .mode           = 0644,
  87                 .proc_handler   = proc_dointvec,
  88         },
  89         {
  90                 .procname       = "int_0003",
  91                 .data           = &test_data.int_0003,
  92                 .maxlen         = sizeof(test_data.int_0003),
  93                 .mode           = 0644,
  94                 .proc_handler   = proc_dointvec,
  95         },
  96         {
  97                 .procname       = "match_int",
  98                 .data           = &match_int_ok,
  99                 .maxlen         = sizeof(match_int_ok),
 100                 .mode           = 0444,
 101                 .proc_handler   = proc_dointvec,
 102         },
 103         {
 104                 .procname       = "boot_int",
 105                 .data           = &test_data.boot_int,
 106                 .maxlen         = sizeof(test_data.boot_int),
 107                 .mode           = 0644,
 108                 .proc_handler   = proc_dointvec,
 109                 .extra1         = SYSCTL_ZERO,
 110                 .extra2         = SYSCTL_ONE,
 111         },
 112         {
 113                 .procname       = "uint_0001",
 114                 .data           = &test_data.uint_0001,
 115                 .maxlen         = sizeof(unsigned int),
 116                 .mode           = 0644,
 117                 .proc_handler   = proc_douintvec,
 118         },
 119         {
 120                 .procname       = "string_0001",
 121                 .data           = &test_data.string_0001,
 122                 .maxlen         = sizeof(test_data.string_0001),
 123                 .mode           = 0644,
 124                 .proc_handler   = proc_dostring,
 125         },
 126         {
 127                 .procname       = "bitmap_0001",
 128                 .data           = &test_data.bitmap_0001,
 129                 .maxlen         = SYSCTL_TEST_BITMAP_SIZE,
 130                 .mode           = 0644,
 131                 .proc_handler   = proc_do_large_bitmap,
 132         },
 133         { }
 134 };
 135
 136 static void test_sysctl_calc_match_int_ok(void)
 137 {
 138         int i;
 139
 140         struct {
 141                 int defined;
 142                 int wanted;
 143         } match_int[] = {
 144                 {.defined = *(int *)SYSCTL_ZERO,        .wanted = 0},
 145                 {.defined = *(int *)SYSCTL_ONE,         .wanted = 1},
 146                 {.defined = *(int *)SYSCTL_TWO,         .wanted = 2},
 147                 {.defined = *(int *)SYSCTL_THREE,       .wanted = 3},
 148                 {.defined = *(int *)SYSCTL_FOUR,        .wanted = 4},
 149                 {.defined = *(int *)SYSCTL_ONE_HUNDRED, .wanted = 100},
 150                 {.defined = *(int *)SYSCTL_TWO_HUNDRED, .wanted = 200},
 151                 {.defined = *(int *)SYSCTL_ONE_THOUSAND, .wanted = 1000},
 152                 {.defined = *(int *)SYSCTL_THREE_THOUSAND, .wanted = 3000},
 153                 {.defined = *(int *)SYSCTL_INT_MAX,     .wanted = INT_MAX},
 154                 {.defined = *(int *)SYSCTL_MAXOLDUID,   .wanted = 65535},
 155                 {.defined = *(int *)SYSCTL_NEG_ONE,     .wanted = -1},
 156         };
 157
 158         for (i = 0; i < ARRAY_SIZE(match_int); i++)
 159                 if (match_int[i].defined != match_int[i].wanted)
 160                         match_int_ok = 0;
 161 }
 162
 163 static int test_sysctl_setup_node_tests(void)
 164 {
 165         test_sysctl_calc_match_int_ok();
 166         test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
 167         if (!test_data.bitmap_0001)
 168                 return -ENOMEM;
 169         sysctl_test_headers.test_h_setup_node = register_sysctl("debug/test_sysctl", test_table);
 170         if (!sysctl_test_headers.test_h_setup_node) {
 171                 kfree(test_data.bitmap_0001);
 172                 return -ENOMEM;
 173         }
 174
 175         return 0;
 176 }
 177
 178 /* Used to test that unregister actually removes the directory */
 179 static struct ctl_table test_table_unregister[] = {
 180         {
 181                 .procname       = "unregister_error",
 182                 .data           = &test_data.int_0001,
 183                 .maxlen         = sizeof(int),
 184                 .mode           = 0644,
 185                 .proc_handler   = proc_dointvec_minmax,
 186         },
 187         {}
 188 };
 189
 190 static int test_sysctl_run_unregister_nested(void)
 191 {
 192         struct ctl_table_header *unregister;
 193
 194         unregister = register_sysctl("debug/test_sysctl/unregister_error",
 195                                    test_table_unregister);
 196         if (!unregister)
 197                 return -ENOMEM;
 198
 199         unregister_sysctl_table(unregister);
 200         return 0;
 201 }
 202
 203 static int test_sysctl_run_register_mount_point(void)
 204 {
 205         sysctl_test_headers.test_h_mnt
 206                 = register_sysctl_mount_point("debug/test_sysctl/mnt");
 207         if (!sysctl_test_headers.test_h_mnt)
 208                 return -ENOMEM;
 209
 210         sysctl_test_headers.test_h_mnterror
 211                 = register_sysctl("debug/test_sysctl/mnt/mnt_error",
 212                                   test_table_unregister);
 213         /*
 214          * Don't check the result.:
 215          * If it fails (expected behavior), return 0.
 216          * If successful (missbehavior of register mount point), we want to see
 217          * mnt_error when we run the sysctl test script
 218          */
 219
 220         return 0;
 221 }
 222
 223 static int __init test_sysctl_init(void)
 224 {
 225         int err;
 226
 227         err = test_sysctl_setup_node_tests();
 228         if (err)
 229                 goto out;
 230
 231         err = test_sysctl_run_unregister_nested();
 232         if (err)
 233                 goto out;
 234
 235         err = test_sysctl_run_register_mount_point();
 236
 237 out:
 238         return err;
 239 }
 240 module_init(test_sysctl_init);
 241
 242 static void __exit test_sysctl_exit(void)
 243 {
 244         kfree(test_data.bitmap_0001);
 245         if (sysctl_test_headers.test_h_setup_node)
 246                 unregister_sysctl_table(sysctl_test_headers.test_h_setup_node);
 247         if (sysctl_test_headers.test_h_mnt)
 248                 unregister_sysctl_table(sysctl_test_headers.test_h_mnt);
 249         if (sysctl_test_headers.test_h_mnterror)
 250                 unregister_sysctl_table(sysctl_test_headers.test_h_mnterror);
 251 }
 252
 253 module_exit(test_sysctl_exit);
 254
 255 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
 256 MODULE_LICENSE("GPL");