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");