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
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 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
57 static 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/ */
74 static 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
131 static 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
141 static 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
151 static struct ctl_table_header *test_sysctl_header;
152
test_sysctl_init(void)153 static 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 }
165 module_init(test_sysctl_init);
166
test_sysctl_exit(void)167 static 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
174 module_exit(test_sysctl_exit);
175
176 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
177 MODULE_LICENSE("GPL");
178
