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         struct ctl_table_header *empty_add;
  39         struct ctl_table_header *empty;
  40 } sysctl_test_headers;
  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       = "match_int",
 100                 .data           = &match_int_ok,
 101                 .maxlen         = sizeof(match_int_ok),
 102                 .mode           = 0444,
 103                 .proc_handler   = proc_dointvec,
 104         },
 105         {
 106                 .procname       = "boot_int",
 107                 .data           = &test_data.boot_int,
 108                 .maxlen         = sizeof(test_data.boot_int),
 109                 .mode           = 0644,
 110                 .proc_handler   = proc_dointvec,
 111                 .extra1         = SYSCTL_ZERO,
 112                 .extra2         = SYSCTL_ONE,
 113         },
 114         {
 115                 .procname       = "uint_0001",
 116                 .data           = &test_data.uint_0001,
 117                 .maxlen         = sizeof(unsigned int),
 118                 .mode           = 0644,
 119                 .proc_handler   = proc_douintvec,
 120         },
 121         {
 122                 .procname       = "string_0001",
 123                 .data           = &test_data.string_0001,
 124                 .maxlen         = sizeof(test_data.string_0001),
 125                 .mode           = 0644,
 126                 .proc_handler   = proc_dostring,
 127         },
 128         {
 129                 .procname       = "bitmap_0001",
 130                 .data           = &test_data.bitmap_0001,
 131                 .maxlen         = SYSCTL_TEST_BITMAP_SIZE,
 132                 .mode           = 0644,
 133                 .proc_handler   = proc_do_large_bitmap,
 134         },
 135 };
 136
 137 static void test_sysctl_calc_match_int_ok(void)
 138 {
 139         int i;
 140
 141         struct {
 142                 int defined;
 143                 int wanted;
 144         } match_int[] = {
 145                 {.defined = *(int *)SYSCTL_ZERO,        .wanted = 0},
 146                 {.defined = *(int *)SYSCTL_ONE,         .wanted = 1},
 147                 {.defined = *(int *)SYSCTL_TWO,         .wanted = 2},
 148                 {.defined = *(int *)SYSCTL_THREE,       .wanted = 3},
 149                 {.defined = *(int *)SYSCTL_FOUR,        .wanted = 4},
 150                 {.defined = *(int *)SYSCTL_ONE_HUNDRED, .wanted = 100},
 151                 {.defined = *(int *)SYSCTL_TWO_HUNDRED, .wanted = 200},
 152                 {.defined = *(int *)SYSCTL_ONE_THOUSAND, .wanted = 1000},
 153                 {.defined = *(int *)SYSCTL_THREE_THOUSAND, .wanted = 3000},
 154                 {.defined = *(int *)SYSCTL_INT_MAX,     .wanted = INT_MAX},
 155                 {.defined = *(int *)SYSCTL_MAXOLDUID,   .wanted = 65535},
 156                 {.defined = *(int *)SYSCTL_NEG_ONE,     .wanted = -1},
 157         };
 158
 159         for (i = 0; i < ARRAY_SIZE(match_int); i++)
 160                 if (match_int[i].defined != match_int[i].wanted)
 161                         match_int_ok = 0;
 162 }
 163
 164 static int test_sysctl_setup_node_tests(void)
 165 {
 166         test_sysctl_calc_match_int_ok();
 167         test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
 168         if (!test_data.bitmap_0001)
 169                 return -ENOMEM;
 170         sysctl_test_headers.test_h_setup_node = register_sysctl("debug/test_sysctl", test_table);
 171         if (!sysctl_test_headers.test_h_setup_node) {
 172                 kfree(test_data.bitmap_0001);
 173                 return -ENOMEM;
 174         }
 175
 176         return 0;
 177 }
 178
 179 /* Used to test that unregister actually removes the directory */
 180 static struct ctl_table test_table_unregister[] = {
 181         {
 182                 .procname       = "unregister_error",
 183                 .data           = &test_data.int_0001,
 184                 .maxlen         = sizeof(int),
 185                 .mode           = 0644,
 186                 .proc_handler   = proc_dointvec_minmax,
 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 struct ctl_table test_table_empty[] = { };
 224
 225 static int test_sysctl_run_register_empty(void)
 226 {
 227         /* Tets that an empty dir can be created */
 228         sysctl_test_headers.empty_add
 229                 = register_sysctl("debug/test_sysctl/empty_add", test_table_empty);
 230         if (!sysctl_test_headers.empty_add)
 231                 return -ENOMEM;
 232
 233         /* Test that register on top of an empty dir works */
 234         sysctl_test_headers.empty
 235                 = register_sysctl("debug/test_sysctl/empty_add/empty", test_table_empty);
 236         if (!sysctl_test_headers.empty)
 237                 return -ENOMEM;
 238
 239         return 0;
 240 }
 241
 242 static int __init test_sysctl_init(void)
 243 {
 244         int err;
 245
 246         err = test_sysctl_setup_node_tests();
 247         if (err)
 248                 goto out;
 249
 250         err = test_sysctl_run_unregister_nested();
 251         if (err)
 252                 goto out;
 253
 254         err = test_sysctl_run_register_mount_point();
 255         if (err)
 256                 goto out;
 257
 258         err = test_sysctl_run_register_empty();
 259
 260 out:
 261         return err;
 262 }
 263 module_init(test_sysctl_init);
 264
 265 static void __exit test_sysctl_exit(void)
 266 {
 267         kfree(test_data.bitmap_0001);
 268         if (sysctl_test_headers.test_h_setup_node)
 269                 unregister_sysctl_table(sysctl_test_headers.test_h_setup_node);
 270         if (sysctl_test_headers.test_h_mnt)
 271                 unregister_sysctl_table(sysctl_test_headers.test_h_mnt);
 272         if (sysctl_test_headers.test_h_mnterror)
 273                 unregister_sysctl_table(sysctl_test_headers.test_h_mnterror);
 274         if (sysctl_test_headers.empty)
 275                 unregister_sysctl_table(sysctl_test_headers.empty);
 276         if (sysctl_test_headers.empty_add)
 277                 unregister_sysctl_table(sysctl_test_headers.empty_add);
 278 }
 279
 280 module_exit(test_sysctl_exit);
 281
 282 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
 283 MODULE_LICENSE("GPL");