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 static int match_int_ok = 1;
42
43 struct test_sysctl_data {
44 int int_0001;
45 int int_0002;
46 int int_0003[4];
47
48 int boot_int;
49
50 unsigned int uint_0001;
51
52 char string_0001[65];
53
54 #define SYSCTL_TEST_BITMAP_SIZE 65536
55 unsigned long *bitmap_0001;
56 };
57
58 static struct test_sysctl_data test_data = {
59 .int_0001 = 60,
60 .int_0002 = 1,
61
62 .int_0003[0] = 0,
63 .int_0003[1] = 1,
64 .int_0003[2] = 2,
65 .int_0003[3] = 3,
66
67 .boot_int = 0,
68
69 .uint_0001 = 314,
70
71 .string_0001 = "(none)",
72 };
73
74 /* These are all under /proc/sys/debug/test_sysctl/ */
75 static struct ctl_table test_table[] = {
76 {
77 .procname = "int_0001",
78 .data = &test_data.int_0001,
79 .maxlen = sizeof(int),
80 .mode = 0644,
81 .proc_handler = proc_dointvec_minmax,
82 .extra1 = &i_zero,
83 .extra2 = &i_one_hundred,
84 },
85 {
86 .procname = "int_0002",
87 .data = &test_data.int_0002,
88 .maxlen = sizeof(int),
89 .mode = 0644,
90 .proc_handler = proc_dointvec,
91 },
92 {
93 .procname = "int_0003",
94 .data = &test_data.int_0003,
95 .maxlen = sizeof(test_data.int_0003),
96 .mode = 0644,
97 .proc_handler = proc_dointvec,
98 },
99 {
100 .procname = "match_int",
101 .data = &match_int_ok,
102 .maxlen = sizeof(match_int_ok),
103 .mode = 0444,
104 .proc_handler = proc_dointvec,
105 },
106 {
107 .procname = "boot_int",
108 .data = &test_data.boot_int,
109 .maxlen = sizeof(test_data.boot_int),
110 .mode = 0644,
111 .proc_handler = proc_dointvec,
112 .extra1 = SYSCTL_ZERO,
113 .extra2 = SYSCTL_ONE,
114 },
115 {
116 .procname = "uint_0001",
117 .data = &test_data.uint_0001,
118 .maxlen = sizeof(unsigned int),
119 .mode = 0644,
120 .proc_handler = proc_douintvec,
121 },
122 {
123 .procname = "string_0001",
124 .data = &test_data.string_0001,
125 .maxlen = sizeof(test_data.string_0001),
126 .mode = 0644,
127 .proc_handler = proc_dostring,
128 },
129 {
130 .procname = "bitmap_0001",
131 .data = &test_data.bitmap_0001,
132 .maxlen = SYSCTL_TEST_BITMAP_SIZE,
133 .mode = 0644,
134 .proc_handler = proc_do_large_bitmap,
135 },
136 { }
137 };
138
139 static struct ctl_table_header *test_sysctl_header;
140
test_sysctl_init(void)141 static int __init test_sysctl_init(void)
142 {
143 int i;
144
145 struct {
146 int defined;
147 int wanted;
148 } match_int[] = {
149 {.defined = *(int *)SYSCTL_ZERO, .wanted = 0},
150 {.defined = *(int *)SYSCTL_ONE, .wanted = 1},
151 {.defined = *(int *)SYSCTL_TWO, .wanted = 2},
152 {.defined = *(int *)SYSCTL_THREE, .wanted = 3},
153 {.defined = *(int *)SYSCTL_FOUR, .wanted = 4},
154 {.defined = *(int *)SYSCTL_ONE_HUNDRED, .wanted = 100},
155 {.defined = *(int *)SYSCTL_TWO_HUNDRED, .wanted = 200},
156 {.defined = *(int *)SYSCTL_ONE_THOUSAND, .wanted = 1000},
157 {.defined = *(int *)SYSCTL_THREE_THOUSAND, .wanted = 3000},
158 {.defined = *(int *)SYSCTL_INT_MAX, .wanted = INT_MAX},
159 {.defined = *(int *)SYSCTL_MAXOLDUID, .wanted = 65535},
160 {.defined = *(int *)SYSCTL_NEG_ONE, .wanted = -1},
161 };
162
163 for (i = 0; i < ARRAY_SIZE(match_int); i++)
164 if (match_int[i].defined != match_int[i].wanted)
165 match_int_ok = 0;
166
167 test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
168 if (!test_data.bitmap_0001)
169 return -ENOMEM;
170 test_sysctl_header = register_sysctl("debug/test_sysctl", test_table);
171 if (!test_sysctl_header) {
172 kfree(test_data.bitmap_0001);
173 return -ENOMEM;
174 }
175 return 0;
176 }
177 module_init(test_sysctl_init);
178
test_sysctl_exit(void)179 static void __exit test_sysctl_exit(void)
180 {
181 kfree(test_data.bitmap_0001);
182 if (test_sysctl_header)
183 unregister_sysctl_table(test_sysctl_header);
184 }
185
186 module_exit(test_sysctl_exit);
187
188 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
189 MODULE_LICENSE("GPL");
190