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
 29static int i_zero;
 30static int i_one_hundred = 100;
 31static int match_int_ok = 1;
 32
 33struct 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
 48static 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/ */
 65static 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
129static struct ctl_table_header *test_sysctl_header;
130
131static 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}
167module_init(test_sysctl_init);
168
169static 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
176module_exit(test_sysctl_exit);
177
178MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
179MODULE_LICENSE("GPL");