xref: /kernel/linux/linux-5.10/lib/test_sysctl.c (revision 8c2ecf20) 
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
39static int i_zero;
40static int i_one_hundred = 100;
41
42struct 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
57static 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/ */
74static 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
131static 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
141static 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
151static struct ctl_table_header *test_sysctl_header;
152
153static 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}
165module_init(test_sysctl_init);
166
167static 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
174module_exit(test_sysctl_exit);
175
176MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
177MODULE_LICENSE("GPL");
178