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 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	unsigned int uint_0001;
 48
 49	char string_0001[65];
 50};
 51
 52static struct test_sysctl_data test_data = {
 53	.int_0001 = 60,
 54	.int_0002 = 1,
 55
 56	.int_0003[0] = 0,
 57	.int_0003[1] = 1,
 58	.int_0003[2] = 2,
 59	.int_0003[3] = 3,
 60
 61	.uint_0001 = 314,
 62
 63	.string_0001 = "(none)",
 64};
 65
 66/* These are all under /proc/sys/debug/test_sysctl/ */
 67static struct ctl_table test_table[] = {
 68	{
 69		.procname	= "int_0001",
 70		.data		= &test_data.int_0001,
 71		.maxlen		= sizeof(int),
 72		.mode		= 0644,
 73		.proc_handler	= proc_dointvec_minmax,
 74		.extra1		= &i_zero,
 75		.extra2         = &i_one_hundred,
 76	},
 77	{
 78		.procname	= "int_0002",
 79		.data		= &test_data.int_0002,
 80		.maxlen		= sizeof(int),
 81		.mode		= 0644,
 82		.proc_handler	= proc_dointvec,
 83	},
 84	{
 85		.procname	= "int_0003",
 86		.data		= &test_data.int_0003,
 87		.maxlen		= sizeof(test_data.int_0003),
 88		.mode		= 0644,
 89		.proc_handler	= proc_dointvec,
 90	},
 91	{
 92		.procname	= "uint_0001",
 93		.data		= &test_data.uint_0001,
 94		.maxlen		= sizeof(unsigned int),
 95		.mode		= 0644,
 96		.proc_handler	= proc_douintvec,
 97	},
 98	{
 99		.procname	= "string_0001",
100		.data		= &test_data.string_0001,
101		.maxlen		= sizeof(test_data.string_0001),
102		.mode		= 0644,
103		.proc_handler	= proc_dostring,
104	},
105	{ }
106};
107
108static struct ctl_table test_sysctl_table[] = {
109	{
110		.procname	= "test_sysctl",
111		.maxlen		= 0,
112		.mode		= 0555,
113		.child		= test_table,
114	},
115	{ }
116};
117
118static struct ctl_table test_sysctl_root_table[] = {
119	{
120		.procname	= "debug",
121		.maxlen		= 0,
122		.mode		= 0555,
123		.child		= test_sysctl_table,
124	},
125	{ }
126};
127
128static struct ctl_table_header *test_sysctl_header;
129
130static int __init test_sysctl_init(void)
131{
132	test_sysctl_header = register_sysctl_table(test_sysctl_root_table);
133	if (!test_sysctl_header)
134		return -ENOMEM;
135	return 0;
136}
137late_initcall(test_sysctl_init);
138
139static void __exit test_sysctl_exit(void)
140{
141	if (test_sysctl_header)
142		unregister_sysctl_table(test_sysctl_header);
143}
144
145module_exit(test_sysctl_exit);
146
147MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
148MODULE_LICENSE("GPL");