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
39 static int i_zero;
40 static int i_one_hundred = 100;
41
42 struct 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
52 static 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/ */
67 static 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
108 static 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
118 static 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
128 static struct ctl_table_header *test_sysctl_header;
129
test_sysctl_init(void)130 static 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 }
137 late_initcall(test_sysctl_init);
138
test_sysctl_exit(void)139 static void __exit test_sysctl_exit(void)
140 {
141 if (test_sysctl_header)
142 unregister_sysctl_table(test_sysctl_header);
143 }
144
145 module_exit(test_sysctl_exit);
146
147 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
148 MODULE_LICENSE("GPL");
149
