1// SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1
2/*
3 * proc sysctl test driver
4 *
5 * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org>
6 */
7
8/*
9 * This module provides an interface to the proc sysctl interfaces.  This
10 * driver requires CONFIG_PROC_SYSCTL. It will not normally be loaded by the
11 * system unless explicitly requested by name. You can also build this driver
12 * into your kernel.
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/init.h>
18#include <linux/list.h>
19#include <linux/module.h>
20#include <linux/printk.h>
21#include <linux/fs.h>
22#include <linux/miscdevice.h>
23#include <linux/slab.h>
24#include <linux/uaccess.h>
25#include <linux/async.h>
26#include <linux/delay.h>
27#include <linux/vmalloc.h>
28
29static int i_zero;
30static int i_one_hundred = 100;
31static int match_int_ok = 1;
32
33
34static struct {
35	struct ctl_table_header *test_h_setup_node;
36	struct ctl_table_header *test_h_mnt;
37	struct ctl_table_header *test_h_mnterror;
38	struct ctl_table_header *empty_add;
39	struct ctl_table_header *empty;
40} sysctl_test_headers;
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	= "match_int",
100		.data		= &match_int_ok,
101		.maxlen		= sizeof(match_int_ok),
102		.mode		= 0444,
103		.proc_handler	= proc_dointvec,
104	},
105	{
106		.procname	= "boot_int",
107		.data		= &test_data.boot_int,
108		.maxlen		= sizeof(test_data.boot_int),
109		.mode		= 0644,
110		.proc_handler	= proc_dointvec,
111		.extra1		= SYSCTL_ZERO,
112		.extra2         = SYSCTL_ONE,
113	},
114	{
115		.procname	= "uint_0001",
116		.data		= &test_data.uint_0001,
117		.maxlen		= sizeof(unsigned int),
118		.mode		= 0644,
119		.proc_handler	= proc_douintvec,
120	},
121	{
122		.procname	= "string_0001",
123		.data		= &test_data.string_0001,
124		.maxlen		= sizeof(test_data.string_0001),
125		.mode		= 0644,
126		.proc_handler	= proc_dostring,
127	},
128	{
129		.procname	= "bitmap_0001",
130		.data		= &test_data.bitmap_0001,
131		.maxlen		= SYSCTL_TEST_BITMAP_SIZE,
132		.mode		= 0644,
133		.proc_handler	= proc_do_large_bitmap,
134	},
135};
136
137static void test_sysctl_calc_match_int_ok(void)
138{
139	int i;
140
141	struct {
142		int defined;
143		int wanted;
144	} match_int[] = {
145		{.defined = *(int *)SYSCTL_ZERO,	.wanted = 0},
146		{.defined = *(int *)SYSCTL_ONE,		.wanted = 1},
147		{.defined = *(int *)SYSCTL_TWO,		.wanted = 2},
148		{.defined = *(int *)SYSCTL_THREE,	.wanted = 3},
149		{.defined = *(int *)SYSCTL_FOUR,	.wanted = 4},
150		{.defined = *(int *)SYSCTL_ONE_HUNDRED, .wanted = 100},
151		{.defined = *(int *)SYSCTL_TWO_HUNDRED,	.wanted = 200},
152		{.defined = *(int *)SYSCTL_ONE_THOUSAND, .wanted = 1000},
153		{.defined = *(int *)SYSCTL_THREE_THOUSAND, .wanted = 3000},
154		{.defined = *(int *)SYSCTL_INT_MAX,	.wanted = INT_MAX},
155		{.defined = *(int *)SYSCTL_MAXOLDUID,	.wanted = 65535},
156		{.defined = *(int *)SYSCTL_NEG_ONE,	.wanted = -1},
157	};
158
159	for (i = 0; i < ARRAY_SIZE(match_int); i++)
160		if (match_int[i].defined != match_int[i].wanted)
161			match_int_ok = 0;
162}
163
164static int test_sysctl_setup_node_tests(void)
165{
166	test_sysctl_calc_match_int_ok();
167	test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
168	if (!test_data.bitmap_0001)
169		return -ENOMEM;
170	sysctl_test_headers.test_h_setup_node = register_sysctl("debug/test_sysctl", test_table);
171	if (!sysctl_test_headers.test_h_setup_node) {
172		kfree(test_data.bitmap_0001);
173		return -ENOMEM;
174	}
175
176	return 0;
177}
178
179/* Used to test that unregister actually removes the directory */
180static struct ctl_table test_table_unregister[] = {
181	{
182		.procname	= "unregister_error",
183		.data		= &test_data.int_0001,
184		.maxlen		= sizeof(int),
185		.mode		= 0644,
186		.proc_handler	= proc_dointvec_minmax,
187	},
188};
189
190static int test_sysctl_run_unregister_nested(void)
191{
192	struct ctl_table_header *unregister;
193
194	unregister = register_sysctl("debug/test_sysctl/unregister_error",
195				   test_table_unregister);
196	if (!unregister)
197		return -ENOMEM;
198
199	unregister_sysctl_table(unregister);
200	return 0;
201}
202
203static int test_sysctl_run_register_mount_point(void)
204{
205	sysctl_test_headers.test_h_mnt
206		= register_sysctl_mount_point("debug/test_sysctl/mnt");
207	if (!sysctl_test_headers.test_h_mnt)
208		return -ENOMEM;
209
210	sysctl_test_headers.test_h_mnterror
211		= register_sysctl("debug/test_sysctl/mnt/mnt_error",
212				  test_table_unregister);
213	/*
214	 * Don't check the result.:
215	 * If it fails (expected behavior), return 0.
216	 * If successful (missbehavior of register mount point), we want to see
217	 * mnt_error when we run the sysctl test script
218	 */
219
220	return 0;
221}
222
223static struct ctl_table test_table_empty[] = { };
224
225static int test_sysctl_run_register_empty(void)
226{
227	/* Tets that an empty dir can be created */
228	sysctl_test_headers.empty_add
229		= register_sysctl("debug/test_sysctl/empty_add", test_table_empty);
230	if (!sysctl_test_headers.empty_add)
231		return -ENOMEM;
232
233	/* Test that register on top of an empty dir works */
234	sysctl_test_headers.empty
235		= register_sysctl("debug/test_sysctl/empty_add/empty", test_table_empty);
236	if (!sysctl_test_headers.empty)
237		return -ENOMEM;
238
239	return 0;
240}
241
242static int __init test_sysctl_init(void)
243{
244	int err;
245
246	err = test_sysctl_setup_node_tests();
247	if (err)
248		goto out;
249
250	err = test_sysctl_run_unregister_nested();
251	if (err)
252		goto out;
253
254	err = test_sysctl_run_register_mount_point();
255	if (err)
256		goto out;
257
258	err = test_sysctl_run_register_empty();
259
260out:
261	return err;
262}
263module_init(test_sysctl_init);
264
265static void __exit test_sysctl_exit(void)
266{
267	kfree(test_data.bitmap_0001);
268	if (sysctl_test_headers.test_h_setup_node)
269		unregister_sysctl_table(sysctl_test_headers.test_h_setup_node);
270	if (sysctl_test_headers.test_h_mnt)
271		unregister_sysctl_table(sysctl_test_headers.test_h_mnt);
272	if (sysctl_test_headers.test_h_mnterror)
273		unregister_sysctl_table(sysctl_test_headers.test_h_mnterror);
274	if (sysctl_test_headers.empty)
275		unregister_sysctl_table(sysctl_test_headers.empty);
276	if (sysctl_test_headers.empty_add)
277		unregister_sysctl_table(sysctl_test_headers.empty_add);
278}
279
280module_exit(test_sysctl_exit);
281
282MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
283MODULE_LICENSE("GPL");
284